Main Article: Building Character Sheets

Learning CSS and HTML can be daunting. And yet, if you want to create a character sheet for Roll20, both are required.

This page gives a number of examples for creative way to leverage the character sheet system. Most of these tips involve CSS and were pulled from the CSS Wizardry thread in the Character Sheets forum, but some tips don't necessarily involve CSS at all.

Many of these tips also include links to a live demo on JSFiddle, so you can see them in action.

Four Ways to Use an Attribute

Standard

Create one of: <input> (with a type attribute of "text", "number", "checkbox", "radio", or "hidden"), <select>, or <textarea>, and set the element's name attribute to a value beginning with "attr_"

<input type="text" name="attr_text_example">
<input type="number" name="attr_number_example">
<input type="checkbox" name="attr_checkbox_example">
<input type="radio" name="attr_radio_example">
<input type="hidden" name="attr_hidden_example" value="0">
<select name="attr_select_example">
    <option value="1">First option</option>
    <option value="2">Second option</option>
</select>
<textarea name="attr_textarea_example"></textarea>

The value of the form element will be stored as the value of an attribute with the same name as the form element, except the "attr_" prefix will be removed. So, an element named "attr_example" will be stored in the attribute "example".

Text inputs, number inputs, and textareas will not update the backing attribute until they lose focus, for example when you click elsewhere on the sheet or hit the [tab] key.

Hidden inputs are, as you might guess, hidden to the user. They cannot be interacted with, and so they are prime candidates for intermediate calculations of autocalc or storing things the user doesn't need to see or change for Sheet Worker Scripts.

If you have multiple radio inputs with the same name, only one of those radios will be checked at any given time. If you have multiple other kinds of elements with the same name, their values will be synchronized. This can be used, for example, if you have a tab layout with the same field present in two tabs. Give them both the same name, and they will always have the same value.

Autocalc Fields

If a field has the disabled attribute, the user will be unable to modify its value and its value will be treated as a mathematical equation (which can reference other attributes of the character). The result of that formula will be what the user sees. Errors in the formula (for example, @{a} + @{b} + @{c} when attribute b has no value) will result in no output.

When using sheet worker scripts, the value of the autocalc field you get from the getAttrs function will be its formula, and you cannot set its value to something else. See sheetworker-autocalc for a utility to resolve autocalc fields to their calculated value in a sheet worker script. Note: sheetworker-autocalc has not been tested with repeating fields.

Readonly Fields

If a field has the readonly attribute, the user will be unable to modify its value, and its default styling will be the same as if it were disabled. However, sheet worker scripts will be able to modify its value, and if its value is some kind of equation, it won't be automatically calculated. Note: If for some reason a readonly field is an equation, sheetworker-autocalc will be able to resolve it to a value just fine.

Attribute-Backed <span>s

A <span> element can be given an "attr_" name, just like one of the form elements, above. This will cause the span to behave similarly to a readonly field in that the user cannot modify it directly, and sheet worker scripts have no trouble doing so. There are two main differences with an attribute backed span:

1. The default styling: the span will look just like the surrounding text
2. When using attribute backed spans in a repeating section, you should always make a hidden input version of the attribute as attribute backed spans in repeating sections cannot be called without the full repeating section syntax (e.g. @{repeating_SECTIONNAME_$X_attribute_name}).

Styling Checkboxes and Radio Buttons

Live Demo

Checkboxes and radio buttons don't like getting changed much. Instead, it can be easier to hide the actual checkbox/radio and put a more cooperative element underneath.

<input type="checkbox"><span></span>
<input type="radio" name="attr_r"><span></span>
<input type="radio" name="attr_r"><span></span>
<input type="radio" name="attr_r"><span></span>
<input type="radio" name="attr_r"><span></span>
<input type="radio" name="attr_r"><span></span>

/* Hide actual radio/checkbox */
input[type="radio"],
input[type="checkbox"] {
    opacity: 0;
    width: 16px;
    height: 16px;
    position: relative;
    top: 5px;
    left: 6px;
    margin: -10px;
    cursor: pointer;
    z-index: 1;
}

/* Fake radio/checkbox */
input[type="radio"] + span::before,
input[type="checkbox"] + span::before {
    margin-right: 4px;
    border: solid 1px #a8a8a8;
    line-height: 14px;
    text-align: center;
    display: inline-block;
    vertical-align: middle;
    box-shadow: 0 0 2px #ccc;
    background: #f6f6f6;
    background: radial-gradient(#f6f6f6, #dfdfdf);
}

/* Fake radio */
input[type="radio"] + span::before {
    content: "";
    width: 12px;
    height: 12px;
    font-size: 24px;
    border-radius: 50%;
}

input[type="radio"]:checked + span::before {
    content: "•";
}

/* Fake checkbox */
input[type="checkbox"] + span::before {
    content: "";
    width: 14px;
    height: 14px;
    font-size: 12px;
    border-radius: 3px;
}

input[type="checkbox"]:checked + span::before {
    content: "✓";
}

The key here is the opacity: 0; set on the actual input, and then the width, height, and content set on the span::before immediately following the input. The checkbox/radio will be on top of the span: invisible, but still clickable. When the checkbox/radio is selected, then, the style on the span::before is changed.

Note: Because of the way this is set up, if you do not have a span element immediately following your checkbox/radio button, the checkbox/radio button will not be visible.

Alternative Checkboxes

Live Demo

You're not restricted to a box with a check on it if you want a binary state (on or off). When styling your checkbox (or radio button!) you can use just about anything.

/* Fake checkbox */
input[type="checkbox"] + span::before {
    margin-right: 4px;
    line-height: 14px;
    text-align: center;
    display: inline-block;
    vertical-align: middle;
    content: "▼";
    width: 14px;
    height: 14px;
    font-size: 12px;
}

input[type="checkbox"]:checked + span::before {
    content: "►";
}

Now, instead of an empty box, or a box with a checkmark, you've got a right-pointing arrow or a down-pointing arrow. You can also use an image instead of a string, such as content: url(http://i.imgur.com/90HuQPr.png);

Fill Radio Buttons to the Left

Live Demo

A number of games use a set of bubbles, filled in from left to right, to represent various traits. Radio buttons can only have one selected value, however, and if we used a set of checkboxes, it would be annoying to make the user click each and every one of them to set the character's attribute. Also, a set of checkboxes would make macros extremely ugly: @{Strength_1} * 1 + @{Strength_2} * 1 + ...

However, with the radio button styling, we can solve this problem and use a radio button anyway, and only have one value.

<input type="radio" name="attr_r" value="1" checked="checked"><span></span>
<input type="radio" name="attr_r" value="2"><span></span>
<input type="radio" name="attr_r" value="3"><span></span>
<input type="radio" name="attr_r" value="4"><span></span>
<input type="radio" name="attr_r" value="5"><span></span>

/* Hide actual radio */
input[type="radio"] {
    opacity: 0;
    width: 16px;
    height: 16px;
    position: relative;
    top: 5px;
    left: 6px;
    margin: -10px;
    cursor: pointer;
    z-index: 1;
}

/* Fake radio */
input[type="radio"] + span::before {
    margin-right: 4px;
    border: solid 1px #a8a8a8;
    line-height: 14px;
    text-align: center;
    display: inline-block;
    vertical-align: middle;
    box-shadow: 0 0 2px #ccc;
    background: #f6f6f6;
    background: radial-gradient(#f6f6f6, #dfdfdf);
    content: "•";
    width: 12px;
    height: 12px;
    font-size: 24px;
    border-radius: 50%;
}

/* Remove dot from all radios _after_ selected one */
input[type="radio"]:checked ~ input[type="radio"] + span::before {    
    content: "";
}

Here, all radio buttons are styled by default to appear as though they're checked. The radio buttons after the one that's actually checked then have the dot removed. The result is that the checked radio button and all of the ones to the left are "filled in," while the ones to the left are empty. You can invert this behavior (right of the checked radio are filled, checked and left of checked are empty) by swapping the two content lines.

To reverse this behavior (checked radio and right of checked radio are filled, left of checked radio are empty), swap the two content lines and change the last selector to this:

input[type="radio"]:checked ~ input[type="radio"] + span::before,
input[type="radio"]:checked + span::before

Note: If no radio button is selected, all of them will appear filled in (or all will appear empty if you've reversed/inverted the CSS). Therefore, it is wise to include checked="checked" on one of the radio buttons. That said, you may desire a "zero" value for the trait in question. I recommend having an extra radio button with value="0" checked="checked" and without the span element immediately following it. This will give you an initial value of 0, your radio button group will appear as intended, and the "zero" value will not show up to the user.

Note: All radio buttons which are siblings will be affected by the selection of one of the radios. It is therefore recommended that you wrap the button group in some element, such as span or div.

Circular Layouts

Live Demo

Some character sheets have rather interesting layouts. Mage: the Ascension, for example, has a pair of traits called Quintessence and Paradox that are both mapped onto a wheel of checkboxes.

<div>
    <div>
        <input type="checkbox" class="sheet-wheel sheet-wheel9 sheet-middle sheet-left-1" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel27 sheet-mid-three-eighth sheet-left-2" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel45 sheet-mid-quarter sheet-left-3" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel63 sheet-mid-eighth sheet-left-4" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel81 sheet-top sheet-left-5" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel99 sheet-top sheet-left-6" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel117 sheet-mid-eighth sheet-left-7" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel135 sheet-mid-quarter sheet-left-8" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel153 sheet-mid-three-eighth sheet-left-9" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel171 sheet-middle sheet-left-10" value="1"><span></span>
    </div>
    <div>
        <input type="checkbox" class="sheet-wheel sheet-wheel171 sheet-middle-2 sheet-left-1" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel153 sheet-mid-five-eighth sheet-left-2" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel135 sheet-mid-three-quarter sheet-left-3" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel117 sheet-mid-seven-eighth sheet-left-4" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel99 sheet-bottom sheet-left-5" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel81 sheet-bottom sheet-left-6" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel63 sheet-mid-seven-eighth sheet-left-7" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel45 sheet-mid-three-quarter sheet-left-8" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel27 sheet-mid-five-eighth sheet-left-9" value="1"><span></span>
        <input type="checkbox" class="sheet-wheel sheet-wheel9 sheet-middle-2 sheet-left-10" value="1"><span></span>
    </div>
    <div class="sheet-marker">•</div>
</div>

/* Hide actual checkbox */
input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 15px;
    height: 15px;
    cursor: pointer;
    z-index: 1;
    margin-top: 6px;
}

/* Fake checkbox */
input[type="checkbox"] + span::before {
    border: solid 1px #a8a8a8;
    line-height: 14px;
    text-align: middle;
    display: inline-block;
    vertical-align: middle;
    box-shadow: 0 0 2px #ccc;
    background: #f6f6f6;
    background: radial-gradient(#f6f6f6, #dfdfdf);
    position: relative;
    content: "";
    width: 14px;
    height: 14px;
    font-size: 12px;
    border-radius: 3px;
}

/* Styles unique to fake checkbox (checked) */
input[type="checkbox"]:checked + span::before {
    content: "✓";
    color: #a00;
    box-shadow: 0 0 2px transparent;
}

/* Position checkboxes vertically in circle */
input.sheet-top  { margin-top: 5px; }
input.sheet-top + span::before { top: 0px; }
input.sheet-mid-eighth { margin-top: 12px; }
input.sheet-mid-eighth + span::before  { top: 7px; }
input.sheet-mid-quarter { margin-top: 27px; }
input.sheet-mid-quarter + span::before  { top: 22px; }
input.sheet-mid-three-eighth { margin-top: 45px; }
input.sheet-mid-three-eighth + span::before  { top: 40px; }
input.sheet-middle { margin-top: 67px; }
input.sheet-middle + span::before  { top: 62px; }
input.sheet-middle-2 { margin-top: 73px; }
input.sheet-middle-2 + span::before  { top: 68px; }
input.sheet-mid-five-eighth { margin-top: 95px; }
input.sheet-mid-five-eighth + span::before  { top: 90px; }
input.sheet-mid-three-quarter { margin-top: 113px; }
input.sheet-mid-three-quarter + span::before  { top: 108px; }
input.sheet-mid-seven-eighth { margin-top: 127px; }
input.sheet-mid-seven-eighth + span::before  { top: 122px; }
input.sheet-bottom { margin-top: 135px; }
input.sheet-bottom + span,
input.sheet-bottom + span::before  { top: 130px; }

/* Position checkboxes horizontally in circle */
input.sheet-left-1 { margin-left: 14px; }
input.sheet-left-1 + span::before  { left: 14px; }
input.sheet-left-2 { margin-left: 1px; }
input.sheet-left-2 + span::before  { left: 1px; }
input.sheet-left-3 { margin-left: -4px; }
input.sheet-left-3 + span::before  { left: -4px; }
input.sheet-left-4 { margin-left: -5px; }
input.sheet-left-4 + span::before  { left: -5px; }
input.sheet-left-5 { margin-left: -2px; }
input.sheet-left-5 + span::before  { left: -2px; }
input.sheet-left-6 { margin-left: 1px; }
input.sheet-left-6 + span::before  { left: 1px; }
input.sheet-left-7 { margin-left: 3px; }
input.sheet-left-7 + span::before  { left: 3px; }
input.sheet-left-8 { margin-left: 2px; }
input.sheet-left-8 + span::before  { left: 2px; }
input.sheet-left-9 { margin-left: -4px; }
input.sheet-left-9 + span::before  { left: -4px; }
input.sheet-left-10 { margin-left: -16px; }
input.sheet-left-10 + span::before  { left: -16px; }

/* Rotate checkboxes */
input.sheet-wheel9,
input.sheet-wheel9 + span::before { transform: rotate(9deg); }
input.sheet-wheel27,
input.sheet-wheel27 + span::before { transform: rotate(27deg); }
input.sheet-wheel45,
input.sheet-wheel45 + span::before { transform: rotate(45deg); }
input.sheet-wheel63,
input.sheet-wheel63 + span::before { transform: rotate(63deg); }
input.sheet-wheel81,
input.sheet-wheel81 + span::before { transform: rotate(81deg); }
input.sheet-wheel99,
input.sheet-wheel99 + span::before { transform: rotate(99deg); }
input.sheet-wheel117,
input.sheet-wheel117 + span::before { transform: rotate(117deg); }
input.sheet-wheel135,
input.sheet-wheel135 + span::before { transform: rotate(135deg); }
input.sheet-wheel153,
input.sheet-wheel153 + span::before { transform: rotate(153deg); }
input.sheet-wheel171,
input.sheet-wheel171 + span::before { transform: rotate(171deg); }

div.sheet-marker {
    margin: 36px 0px 0px 5px;
    font-size: 20px;
}

Styling Select Dropdowns

Live Demo

<select> elements are notoriously difficult to apply most styles to. However, using :hover pseudo-selectors and radio buttons, you can create something approximating a dropdown with whatever style you like.

<div class="sheet-container">
    <div class="sheet-child">
        <input type="radio" name="attr_radio" class="sheet-select-radio sheet-d4" value="1" checked="true" />
        <label>d4</label>
        <input type="radio" name="attr_radio" class="sheet-select-radio sheet-d8" value="2" />
        <label>d8</label>
        <div class="sheet-d4"></div>
        <div class="sheet-d8"></div>
    </div>
</div>

.sheet-container {
    width: 280px;
}

.sheet-container,
.sheet-child {
    display: inline-block;
}

.sheet-child {
    vertical-align: middle;
    width: 35px;
    height: 35px;
}

.sheet-child input,
.sheet-child input + label {
    display: none;
    z-index: 1;
}

.sheet-child:hover {
    background: gray;
    position:absolute;
    width: 100px;
    height: auto;
    z-index: 1;
    padding: 5px;
}

.sheet-child:hover > div.sheet-d4 {
    display: none;
}

.sheet-child:hover input,
.sheet-child:hover input + label {
    display: inline;
}

.sheet-child:hover input + label {
   margin-right: 50%
}

.sheet-child:hover label {
    display: inline-block;
}

div.sheet-d4 {
    background-position: -411px -1px;
    width: 35px;
    height: 35px;
    background-image: url("https://i.imgur.com/zkgyBOi.png");
    background-repeat: no-repeat;
    color: transparent;
    display: none;
}

div.sheet-d8 {
    background-position: -703px -1px;
    width: 35px;
    height: 35px;
    background-image: url("https://i.imgur.com/zkgyBOi.png");
    background-repeat: no-repeat;
    color: transparent;
    display: none;
}

.sheet-child:not(:hover) input.sheet-select-radio.sheet-d4:checked ~ div.sheet-d4,
.sheet-child:not(:hover) input.sheet-select-radio.sheet-d8:checked ~ div.sheet-d8 {
    display: block;
}

Styling Select Dropdowns Text

Here's another method to edit text within a select. Use an input with type="hidden" given the same attribute name as the select to trigger css styles on the select's option text.

<input name="attr_favcolor" type="hidden" class="sheet-color-switch">
<select name="attr_favcolor" class="sheet-color-select1">
  <option style="color:red;" value="0" selected>Red</option>
  <option style="color:yellow;" value="1">Yellow</option>
  <option style="color:blue;" value="2">Blue</option>
</select>

.sheet-color-switch[value="0"] + .sheet-color-select1 {color: red;}
.sheet-color-switch[value="1"] + .sheet-color-select1 {color: yellow;}
.sheet-color-switch[value="2"] + .sheet-color-select1 {color: blue;}

Custom Progress Bar

To create a custom progress bar, i use css and sheet worker to update an hidden field:

Live Demo

<div class="sheet-container">
<input type="hidden" value="2" name="attr_Character_overweight" class="sheet-hidden sheet-overweight">
<div class="sheet-overweight"></div>
</div>

div.sheet-overweight {
    width: 90%;
    height: 20px;
    border: 1px solid black;
    color: black;
    text-align: center;
}
input.sheet-overweight[value="0"] ~ div.sheet-overweight {
    background: white;
}
input.sheet-overweight[value="1"] ~ div.sheet-overweight {
    background: linear-gradient(to left, white 60%, green 75%);    
}
input.sheet-overweight[value="2"] ~ div.sheet-overweight {
    background: linear-gradient(to left, white 40%, yellow 75%);
}
    input.sheet-overweight[value="2"] ~ div.sheet-overweight:before {
        content:"Bags half full";
    }
input.sheet-overweight[value="3"] ~ div.sheet-overweight {
    background: linear-gradient(to left, white 20%, orange 75%);
}
    input.sheet-overweight[value="3"] ~ div.sheet-overweight:before {
        content: "Bags nearly full";
    }
input.sheet-overweight[value="4"] ~ div.sheet-overweight {
    background: linear-gradient(to left, white, red 100%);
}
    input.sheet-overweight[value="4"] ~ div.sheet-overweight:before {
        content: "Bags full !";
    }
input.sheet-overweight[value="5"] ~ div.sheet-overweight {
    background: black;
    color: white;
}
    input.sheet-overweight[value="5"] ~ div.sheet-overweight:before {
        content: "Bags too heavy !";
}

Styling Repeating Sections

It's possible to style your repeating sections in a variety of ways. However, you can't just write your CSS as though the <fieldset> that's in your HTML source is what the user is viewing. After writing the code for your repeating section, here is how it will look when rendered to the user:

<fieldset class="repeating_my-repeating-section" style="display: none;">
    <!-- my-repeating-section HTML -->
</fieldset>
<div class="repcontainer" data-groupname="repeating_my-repeating-section">
    <div class="repitem">
        <div class="itemcontrol">
            <button class="btn btn-danger pictos repcontrol_del">#</button>
            <a class="btn repcontrol_move">≡</a>
        </div>
        <!-- my-repeating-section HTML -->
    </div>
    <!-- there will be a div.repitem for each item the user has actually added to the sheet -->
</div>
<div class="repcontrol" data-groupname="repeating_my-repeating-section">
    <button class="btn repcontrol_edit">Modify</button>
    <button class="btn repcontrol_add">+Add</button>
</div>

When you click the Modify button, the Add button is is set to display: none and the text of the Modify button is changed to "Done". When you click Done, the Add button is set to display: inline-block and the text of the Done button is changed to "Modify". While modifying repitems, the repcontainer gains the class "editmode".

Armed with this knowledge, you can do numerous things to alter how your repeating sections are displayed on the final character sheet. For example, you can have multiple repeating items per row:

.repcontainer[data-groupname="repeating_example"] > .repitem {
    display: inline-block;
}

Note: You do not prefix the rep* classes with sheet-!

Remember to use the [data-groupname="repeating_..."] attribute selector if you want to only apply the style to a single repeating section. Of course, if you want the style to affect all of your repeating sections, that's not needed.

What Can't You Do?

You cannot:

• Change the "display" property of the original <fieldset>.
• Change the text of the Add, Modify/Done, Delete, or Move buttons.
  • However, you could set their opacity to 0 and display something in their place, much like styling checkboxes and radios, as well as add ::before or ::after pseudo-elements to them.
• Change the "display" property of the Add button after the user has pressed Modify once.

Counting Items

Live Demo

CSS can let you count things. This can be applied in multiple contexts for character sheets, but one option is to count how many repeating items are in your repeating section:

<div class="sheet-repeating-fields">
    <fieldset class="repeating_my-repeating-section">
        <span class="sheet-counter"></span>
        <input type="text" name="attr_example">
    </fieldset>
</div>

.sheet-repeating-fields {
  counter-reset: sheet-rep-items;
}

.sheet-counter::before {
  counter-increment: sheet-rep-items;
  content: counter(sheet-rep-items) '. ';
}

Filter Repeating section displays according to criteria within the repeating items itself

Assume you want a tabbed section to organize/display spells. All the 1st circle spells are displayed under tab 1, all the 2nd circle spells under tab 2, Etc. One way to do this is to duplicate the html code for each spell level. You have 10 lists, and the tabs choose which of the 10 lists to display. The following code shows how to have one list, but to filter the list so it only displays certain spells.

The HTML looks something like this.

    <span class="sheet-fixed-width" style="width: 11em;"><b> Spell List </b></span><br>
    <input type="radio" name="attr_tab-spells" class="sheet-tab sheet-spells-tab0" value="0" title="All circles" checked style="margin-left:1px;"/>
    <span class="sheet-tab sheet-spells-tab0">All</span>
    <input type="radio" name="attr_tab-spells" class="sheet-tab sheet-spells-tab1" value="1" title="Circle 1"/>
    <span class="sheet-tab sheet-spells-tab1">Circle 1</span>
    <input type="radio" name="attr_tab-spells" class="sheet-tab sheet-spells-tab2" value="2" title="Circle 2"/>
    <span class="sheet-tab sheet-spells-tab2">Circle 2</span>
    <input type="radio" name="attr_tab-spells" class="sheet-tab sheet-spells-tab3" value="3" title="Circle 3"/>
    <span class="sheet-tab sheet-spells-tab3">Circle 3</span>

    <div class="sheet-section sheet-section-sp-list">
        <fieldset class="repeating_spell">
            <input type="radio" name="attr_SP_Circle" class="sheet-hidden sheet-spells-tab0" value="0" checked />
            <input type="radio" name="attr_SP_Circle" class="sheet-hidden sheet-spells-tab1" value="1"/>
            <input type="radio" name="attr_SP_Circle" class="sheet-hidden sheet-spells-tab2" value="2"/>
            <input type="radio" name="attr_SP_Circle" class="sheet-hidden sheet-spells-tab3" value="3"/>
            <div class="sheet-filtered-box">
                <span><select name="attr_SP_Circle" class="sheet-nowrap sheet-label-down" style="width:5em;">
                    <option value="0" selected title"Please choose the circle for this spell.">-</option>
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                </select>Circle</span>
                <span class="sheet-nowrap">
                        <input name="attr_SP_Name" type="text" style="width:12em;" placeholder="Spell Name" ></span>

More fields.
            </div>
        </fieldset>
    </div>

The relevant part of the css looks like this.

div.sheet-section-sp-list {
	max-height: 999999px;
	visibility: visible;
	opacity: 1;
	transition: opacity 0.5s linear 0s;
	overflow: hidden;
}

.charsheet .repcontainer .repitem,          /* A filterbox should look exactly like a repitem.  */
.sheet-filtered-box {
    padding: 5px 5px 2px 5px;
    margin: 5px;
	border: 2px solid #CCCCCC;
	border-radius: 3px;
}

.repcontainer .repitem {
    overflow: hidden;
}

.sheet-section-sp-list>fieldset.repeating_spell+.repcontainer>.repitem {     /* A repitem within a spellslist should functionally not exist, it's place is taken by a filterbox. */
    padding: 0px;
    margin: 0px;
    border: none;
	border-radius:;
}

.sheet-filtered-box {       /* By default, display no items of a filter box */
    display: none;
}
            /* Decide which specific repitems to display.  */
input.sheet-spells-tab0:checked~.sheet-filtered-box,      /* Always display all spells of circle zero.  */
.sheet-spells-tab0:checked~.sheet-section-sp-list>fieldset.repeating_spell+.repcontainer>.repitem .sheet-filtered-box,  /* When tab0 is checked, display everything no matter what which of the inner boxes are checked. */
.sheet-spells-tab1:checked~.sheet-section-sp-list>fieldset.repeating_spell+.repcontainer>.repitem input.sheet-spells-tab1:checked~.sheet-filtered-box,
.sheet-spells-tab2:checked~.sheet-section-sp-list>fieldset.repeating_spell+.repcontainer>.repitem input.sheet-spells-tab2:checked~.sheet-filtered-box,
.sheet-spells-tab3:checked~.sheet-section-sp-list>fieldset.repeating_spell+.repcontainer>.repitem input.sheet-spells-tab3:checked~.sheet-filtered-box {
	display: block;
} 

So basically what this does is it makes a filterbox look exactly like a repitem. By default, no filterboxes are displayed. The last css entries basically say where tab X above the repeating field is checked, and the same radio button inside a specific repitem is checked, then display that item.

Duplicate a repeating section name to display the same data on more than one tab.or present a summary of the data elsewhere

I am not certain that this trick is recommended by the developers, but as of this writing, it works.

You can put the same repeating section name in your html more than once in order to display the same information in multiple styles. You can have individual items displayed one way in one instance of the section (for example as a list of select/options) and a different way (for example as a read only text field) elsewhere. It is extremely useful to combine this trick with the previous section (filtering), so that only a select subset are displayed in different places, but you can do this with the convenience of having the data stored once in one list.

For example, on one tab you can have lots of fiddly options and choices, but on another tab you can display the same list of data pared down to it's minimalist essentials. If the user needs the full list, he can go to the details tab. But the items he uses most frequently fit compactly in a section of another tab. In ether case he is looking at, and manipulating the same list of data, not a list and a separate copy.

Here are the rules:

• You can repeat repeating section names. Each repeated section will share the same rows and items, but each can present the data in a different way. For example : <fieldset class="repeating_weapons sheet-filtershortlist sheet-filtersummarylist"> the additional class tags can be used to differentiate how this section is to be styled as opposed to other repeating_weapons lists display the data.
• Not all items must be present or displayed in all lists. However each item must be present in every list in which it is used. For example, if you have an auto-calc field, or a button that uses a field, All the fields used in the autocalc, or passed by the button, must be present in the same instance of the repeating section, it will not go looking for it in other instances of the repeating section. The referenced field may be hidden, but must be present.
• You can change how fields are presented. For example they can be editable in one instance, but readonly in another.
• If you change repitem to inline-block, it will float "rows" up so that it can display more than one per line.

fieldset.sheet-filtersummarylist+.repcontainer .repitem {
  display: inline-block;
  margin-right: 2em;
}

• If you want the user to only add or modify items in one place, you can get rid of the Add/Modify buttons in the other places by simply adding display: none: to a set of tags similar to this: fieldset.sheet-filtershortlist~.repcontrol where of course the .sheet tag is whatever tag you specify in your html.

Hide Areas

Live Demo

You can hide areas on the character sheet based on the state of a checkbox. Instead of the adjacent sibling selector (+) used by custom checkboxes, you should use the sibling selector (~).

<div>
    <input type="checkbox" class="sheet-arrow">
    <h4>Stuff and Things</h4>
    <div class="sheet-body">
        <input type="text" placeholder="Name" name="attr_name"><br>
        <input type="text" placeholder="Description" name="attr_description">
        <input type="number" min="0" max="20" value="0" name="attr_level"><br>
        <textarea placeholder="Fulltext" name="attr_bio"></textarea>
    </div>
</div>
<div>
    <input type="checkbox" class="sheet-arrow">
    <h4>More Stuff</h4>
    <div class="sheet-body">
        <input type="text" placeholder="Name" name="attr_alternative-name"><br>
        <input type="text" placeholder="Description" name="attr_alternative-description">
        <input type="number" min="0" max="20" value="0" name="attr_alternative-level"><br>
        <textarea placeholder="Fulltext" name="attr_alternative-bio"></textarea>
    </div>
</div>
<div>
    <input type="checkbox" class="sheet-arrow">
    <h4>Other Things</h4>
    <div class="sheet-body">
        <input type="text" placeholder="Name" name="attr_class-name"><br>
        <input type="text" placeholder="Description" name="attr_class-description">
        <input type="number" min="0" max="20" value="0" name="attr_class-level"><br>
        <textarea placeholder="Fulltext" name="class-bio"></textarea>
    </div>
</div>

input.sheet-arrow {
    float: left;
}

input.sheet-arrow:checked ~ div.sheet-body {
    display: none;
}

Whenever one of the checkboxes in this example is checked, the following div becomes hidden.

Swap Visible Areas

Live Demo

You can apply the hide areas logic to multiple elements based on the same checkbox, and get swappable behavior:

<div>
  <input type="checkbox" class="sheet-block-switch">
  <div class="sheet-block-a">
    Lorem ipsum dolor sit amet
  </div>
  <div class="sheet-block-b">
    consectetur adipiscing elit
  </div>
</div>

.sheet-block-a,
.sheet-block-switch:checked ~ .sheet-block-b {
  display: block;
}

.sheet-block-b,
.sheet-block-switch:checked ~ .sheet-block-a {
  display: none;
}

Tabs

This is a short and simple example of implementing tabs on a character sheet, created by Finderski & GiGs.

<div>
    <button type="action" name="act_character" >Character</button>
    <button type="action" name="act_journal" >Journal</button>
    <button type="action" name="act_configuration" >Configuration</button>
</div>
<input type='hidden' class='sheet-tabstoggle' name='attr_sheetTab'  value='character'  />

<div class='sheet-character'>
    <h2>Character</h2>
    <span>character Stuff Goes here </span>
</div>
<div class='sheet-journal'>
    <h2>Journal/Notes</h2>
    <span>Journal/Notes Stuff Goes here</span> 
</div>
<div class='sheet-config'>
    <h2>Config/Settings</h2>
    <span>Sheet Config/Settings goes here</span> 
</div>

<script type="text/worker">
    const buttonlist = ["character","journal","configuration"];
    buttonlist.forEach(button => {
        on(`clicked:${button}`, function() {
            setAttrs({
                sheetTab: button
            });
        });
    });
</script>

/*Configure the tab buttons*/
.sheet-character,
.sheet-config,
.sheet-journal {
	display: none;
}

/* show the selected tab */
.sheet-tabstoggle[value="character"] ~ div.sheet-character,
.sheet-tabstoggle[value="configuration"] ~ .sheet-config,
.sheet-tabstoggle[value="journal"] ~ div.sheet-journal {
	display: block;
}

<input type="radio" name="attr_tab" class="sheet-tab sheet-tab1" value="1" checked="checked"><span title="First Tab"></span>
<input type="radio" name="attr_tab" class="sheet-tab sheet-tab2" value="2"><span title="Second Tab"></span>
<input type="radio" name="attr_tab" class="sheet-tab sheet-tab3" value="3"><span title="Third Tab"></span>
<input type="radio" name="attr_tab" class="sheet-tab sheet-tab4" value="4"><span title="Fourth Tab"></span>

<div class="sheet-tab-content sheet-tab1">
    <h1>Tab 1</h1>
    Lorem ipsum dolor sit amet
</div>

<div class="sheet-tab-content sheet-tab2">
    <h1>Tab the Second</h1>
    consectetur adipisicing elit
</div>

<div class="sheet-tab-content sheet-tab3">
    <h1>3rd Tab</h1>
    sed do eiusmod tempor incididunt ut labore et dolore magna aliqua
</div>

<div class="sheet-tab-content sheet-tab4">
    <h1>Fourth Tab</h1>
    Ut enim ad minim veniam
</div>

div.sheet-tab-content { display: none; }

input.sheet-tab1:checked ~ div.sheet-tab1,
input.sheet-tab2:checked ~ div.sheet-tab2,
input.sheet-tab3:checked ~ div.sheet-tab3,
input.sheet-tab4:checked ~ div.sheet-tab4 { display: block; }

input.sheet-tab {
    width: 150px;
    height: 20px;
    position: relative;
    top: 5px;
    left: 6px;
    margin: -1.5px;
    cursor: pointer;
    z-index: 1;
    opacity: 0;
}

input.sheet-tab + span::before {
    content: attr(title);
    border: solid 1px #a8a8a8;
    border-bottom-color: black;
    text-align: center;
    display: inline-block;
    background: #fff;
    background: linear-gradient(to top, #c8c8c8, #fff, #c8c8c8);
    width: 150px;
    height: 20px;
    font-size: 18px;
    position: absolute;
    top: 12px;
    left: 13px;
}

input.sheet-tab:checked + span::before {
    background: #dcdcdc;
    background: linear-gradient(to top, #fcfcfc, #dcdcdc, #fcfcfc);
    border-bottom-color: #fff;
}

input.sheet-tab:not(:first-child) + span::before { border-left: none; }

input.sheet-tab2 + span::before {
    background: #fee;
    background: linear-gradient(to top, #f8c8c8, #fee, #f8c8c8);
    left: 163px;
}

input.sheet-tab2:checked + span::before {
    background: #dcdcdc;
    background: linear-gradient(to top, #fcecec, #f8c8c8, #fcecec);
    border-bottom-color: #fcecec;
}

input.sheet-tab3 + span::before { left: 313px; }

input.sheet-tab4 + span::before { left: 463px; }

div.sheet-tab-content {
    border: 1px solid #a8a8a8;
    border-top-color: #000;
    margin: 2px 0 0 5px;
    padding: 5px;
}

div.sheet-tab2 { background-color: #fcecec; }

Hexagons

Live demo

<div class="sheet-hex sheet-hex-3" style="background-color: #444; width: 100px; height: 57px">		
    <div class="sheet-inner">
        <h4>Stat</h4>
        <input type="number" style="width: 50%">
    </div>		
    <div class="sheet-corner-1"></div>
    <div class="sheet-corner-2"></div>		
</div>

.sheet-hex {
    width: 100px;
    height: 57px;
    background-color: #ccc;
    background-repeat: no-repeat;
    background-position: 50% 50%;			
    background-size: auto 173px;							
    position: relative;
    float: left;
    margin: 25px 5px;
    text-align: center;
    zoom: 1;
}

.sheet-hex.sheet-hex-gap {
    margin-left: 86px;
}

.sheet-hex a {
    display: block;
    width: 100%;
    height: 100%;
    text-indent: -9999em;
    position: absolute;
    top: 0;
    left: 0;
}

.sheet-hex .sheet-corner-1,
.sheet-hex .sheet-corner-2 {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: inherit;								
    z-index: -2;						
    overflow: hidden;		
    backface-visibility: hidden;			
}

.sheet-hex .sheet-corner-1 {
    z-index:-1;
    transform: rotate(60deg);
}

.sheet-hex .sheet-corner-2 {
    transform: rotate(-60deg);
}

.sheet-hex .sheet-corner-1::before,
.sheet-hex .sheet-corner-2::before {
    width: 173px;
    height: 173px;
    content: '';
    position: absolute;
    background: inherit;
    top: 0;
    left: 0;
    z-index: 1;
    background: inherit;
    background-repeat: no-repeat;
    backface-visibility: hidden;				  
}

.sheet-hex .sheet-corner-1::before {
    transform: rotate(-60deg) translate(-87px, 0px);	
    transform-origin: 0 0;
}

.sheet-hex .sheet-corner-2::before {
    transform: rotate(60deg) translate(-48px, -11px);	
    bottom: 0;
}

/* Custom styles*/
.sheet-hex .sheet-inner { color: #eee; }

.sheet-hex h4 {
    font-family: 'Josefin Sans', sans-serif;		
    margin: 0;			
}

.sheet-hex hr {
    border: 0;
    border-top: 1px solid #eee;
    width: 60%;
    margin: 15px auto;
}

.sheet-hex p {
    font-size: 16px;
    font-family: 'Kotta One', serif;
    width: 80%;
    margin: 0 auto;
}

.sheet-hex.sheet-hex-1 { background: #74cddb; }
.sheet-hex.sheet-hex-2 { background: #f5c53c; }
.sheet-hex.sheet-hex-3 { background: #80b971; }

Note: Make sure the hexagon's width is 57% of the hexagon's height.

Clocks

Live Demo

CSS gradients can do all kinds of interesting things. Here's an example of creating a clock-shaped representation of a value:

<div class="sheet-harm-section">
  <input type="radio" value="0" name="attr_harm" class="sheet-harm-checkbox sheet-harm-0" checked>0
  <input type="radio" value="1" name="attr_harm" class="sheet-harm-checkbox sheet-harm-3">3
  <input type="radio" value="2" name="attr_harm" class="sheet-harm-checkbox sheet-harm-6">6
  <input type="radio" value="3" name="attr_harm" class="sheet-harm-checkbox sheet-harm-9">9
  <input type="radio" value="4" name="attr_harm" class="sheet-harm-checkbox sheet-harm-10">10
  <input type="radio" value="5" name="attr_harm" class="sheet-harm-checkbox sheet-harm-11">11
  <input type="radio" value="6" name="attr_harm" class="sheet-harm-checkbox sheet-harm12">12
  <hr>
  <div class="sheet-clock"></div>
</div>

.sheet-harm-section {
    display: inline-block;
    text-align: center;
}

.sheet-clock {
    width: 5em;
    height: 5em;
    display: inline-block;
    border-radius: 50%;
    background: black;
    border: 2px solid black;
}

.sheet-harm-checkbox.sheet-harm-0:checked ~ .sheet-clock {
    background: white;
}

.sheet-harm-checkbox.sheet-harm-3:checked ~ .sheet-clock {
    background-image: linear-gradient(180deg, transparent 50%, white 50%),
                      linear-gradient(90deg, white 50%, transparent 50%);
}

.sheet-harm-checkbox.sheet-harm-6:checked ~ .sheet-clock {
    background-image: linear-gradient(90deg, white 50%, transparent 50%);
}

.sheet-harm-checkbox.sheet-harm-9:checked ~ .sheet-clock {
    background-image: linear-gradient(180deg, transparent 50%, black 50%),
                      linear-gradient(90deg, white 50%, transparent 50%);
}

.sheet-harm-checkbox.sheet-harm-10:checked ~ .sheet-clock {
    background-image: linear-gradient(210deg, transparent 50%, black 50%),
                      linear-gradient(90deg, white 50%, transparent 50%);
}

.sheet-harm-checkbox.sheet-harm-11:checked ~ .sheet-clock {
    background-image: linear-gradient(240deg, transparent 50%, black 50%),
                      linear-gradient(90deg, white 50%, transparent 50%);
}

.sheet-harm-checkbox.sheet-harm-12:checked ~ .sheet-clock {
    background-color: black;
}

Cycling Button

Live Demo

You can't make a button that rotates through a list, changing a displayed value. However, you can fake it!

The trick lies in layering the radio buttons on top of one another, and changing the z-index based on which input is checked.

• First, set all of the inputs to some baseline z-index.
• Set the first radio input of the group to a z-index higher than the rest.
• For each input, when it is checked, set the z-index of the next input to something higher than the first input. You don't need to do anything for when the last input is selected, as they'll all be back at their default z-index (which means the first one is on top).

When the first input is selected, only the second one will be visible, so you can't click on any other value. When the second is clicked, the third will become the only one you can click on, and so on. The user can also navigate back and forth using arrow keys, or a combination of the tab key (or shift+tab) and the space bar.

<div class="sheet-damage-box">
    <input type="radio" class="sheet-damage-box sheet-no-damage" name="attr_damage-box" value="0" checked>
    <input type="radio" class="sheet-damage-box sheet-bashing-damage" name="attr_damage-box" value="1">
    <input type="radio" class="sheet-damage-box sheet-lethal-damage" name="attr_damage-box" value="2">
    <input type="radio" class="sheet-damage-box sheet-aggravated-damage" name="attr_damage-box" value="3">

    <span class="sheet-damage-box sheet-no-damage">☐ (no damage)</span>
    <span class="sheet-damage-box sheet-bashing-damage">&nbsp;/&nbsp; (bashing damage)</span>
    <span class="sheet-damage-box sheet-lethal-damage">☓ (lethal damage)</span>
    <span class="sheet-damage-box sheet-aggravated-damage">✱ (aggravated damage)</span>
</div>

div.sheet-damage-box {
    width: 195px;
    height: 30px;
    position: relative;
}

input.sheet-damage-box {
    width: 30px;
    height: 30px;
    position: absolute;
    z-index: 1;
}

span.sheet-damage-box {
    margin: 10px 0 0 40px;
    display: none;
}

input.sheet-no-damage { z-index: 2; }

input.sheet-no-damage:checked + input.sheet-bashing-damage,
input.sheet-bashing-damage:checked + input.sheet-lethal-damage,
input.sheet-lethal-damage:checked + input.sheet-aggravated-damage { z-index: 3; }

input.sheet-no-damage:checked ~ span.sheet-no-damage,
input.sheet-bashing-damage:checked ~ span.sheet-bashing-damage,
input.sheet-lethal-damage:checked ~ span.sheet-lethal-damage,
input.sheet-aggravated-damage:checked ~ span.sheet-aggravated-damage { display: inline-block; }

As you can see, this uses the show/hide areas technique to display a span with some text for each radio input. You could also display an image, an input field, an entire section of the charactersheet, whatever you like.

One fancy option would be to combine this with the technique to style your radio buttons. Hide the radios with opacity: 0, and display an image in the same location as the radio button (make sure the image is at a lower z-index than the invisible buttons!) so that the user is apparently clicking on the displayed image to change it.

Sheet Settings

Many official sheets like GUMSHOE have a "Sheet Settings" that can be accessed through a cog icon, which have many options to introduce changes to the sheet at will.

The options are documented in the game's .json file under "useroptions" tag and the rest of course in html/css.

More info can be found in this forum post

Custom Fonts

Roll20 supports five fonts (Arial, Patrick Hand, Contrail One, Shadows Into Light and Candal). It's still possible to use custom fonts, but it's not guaranteed to work and requires the user who want to see them to disable browser brower security to allow "unsecure scripts" to either allow Roll20 to search for locally installed fonts or import a font from an URL.

Starfinder HUD is an example of a sheet using custom font, and having a fallback font if the user doesn't allow unsafe scripts.

@font-face{/*The aldrich font*/
    font-family:Aldrich;
    src:local('Aldrich'),local('Aldrich-Regular'),url(https://kurohyou.github.io/Starfinder-Character-Sheet/Sheet%20Fonts/Aldrich-Regular.ttf);
}

* {
    font-family:Aldrich,Copperplate,Monospace;
}

In the segment above, @font-face defines the name and source of the font. It first asks the broswer if the font exists locally, and if it isn't locally installed, the url gives a location to download the url from.

Here is a list of Web-safe fonts that comes preinstalled on most operating systems, which helps avoiding the need to find a source where the font is hosted online. This search through Roll20's sheet repository shows other sheet that also use custom fonts.

Icon Fonts

An icon font is a font which has pictures instead of letters. You can specify one of the icon fonts below with the font-family property. For example, something like:

<p>A Gem: <span style="font-family: 'Pictos Three'">a</span></p>

Would produce:

A Gem: a

Pictos

Pictos Custom

Pictos Three

dicefontd4

dicefontd6

dicefontd8

dicefontd10

dicefontd12

dicefontd20

dicefontd30

fontello

Styling Roll Buttons

Want a roll button that doesn't have a d20 image in it? Simple!

button[type=roll].sheet-blank-roll-button::before { content: ''; }

The d20 is a single character with the dicefontd20 font-family in the button's ::before pseudo-element. Setting the content to an empty string removes it. If you want to put something other than a d20 in its place, you'll have to change the font-family as well.

Replicating the JavaScript Math Library

Note: With the advent of Sheet Worker Scripts, the value of these tricks is diminished, as you can use the Math library directly with a sheet worker. However, they are kept here for legacy purposes, and because they still work.

It is possible to replicate most of the functionality of JavaScript's Math library with autocalc fields. While this isn't technically CSS Wizardry, it is included in this article for ease of discovery. Functions with an asterisk (*) produce approximate results; you can increase their accuracy by adding iterations to the computation.

Some functions below may reference other functions below.

Constants

The following are constants in JavaScript, so there's no reason to not have them as constants if you happen to need them.

E

E is Euler's constant, the base for the natural logarithm. The exact value is Sum[1 / n!, {n, 0, Infinity}]. Math.log(Math.E) is 1.

<input type="hidden" name="attr_cE" value="2.718281828459045">

LN2

LN2 is the value of Math.log(2).

<input type="hidden" name="attr_cLN2" value="0.6931471805599453">

LN10

LN10 is the value of Math.log(10).

<input type="hidden" name="attr_cLN10" value="2.302585092994046">

LOG2E

LOG2E is the base-2 logarithm of E. In other words, the value of Math.log2(Math.E), or 1 / Math.log(2).

<input type="hidden" name="attr_cLOG2E" value="1.4426950408889634">

LOG10E

LOG10E is the base-10 logarithm of E. In other words, the value of Math.log10(Math.E), or 1 / Math.log(10).

<input type="hidden" name="attr_cLOG10E" value="0.4342944819032518">

PI

PI is the radio between the circumference and diameter of a circle.

<input type="hidden" name="attr_cPI" value="3.141592653589793">

SQRT1_2

SQRT1_2 is the square root of 1/2 (0.5).

<input type="hidden" name="attr_cSQRT1_2" value="0.7071067811865476">

SQRT2

SQRT2 is the square root of 2.

<input type="hidden" name="attr_cSQRT2" value="1.4142135623730951">

Trivially Represented

The following functions you can use in autocalc fields easily, either because they're simple or because they're directly available.

abs(x)

If x < 0, the result is -1 * x. Otherwise, the result is x.

<input type="hidden" name="attr_abs" value="abs(@{x})" disabled>

cbrt(x)

Cube root: cbrt(x)^3 = x.

<input type="hidden" name="attr_cbrt" value="(@{x}**(1/3))" disabled>

ceil(x)

Rounds towards positive infinity.

<input type="hidden" name="attr_ceil" value="ceil(@{x})" disabled>

exp(x)

E^x.

<input type="hidden" name="attr_exp" value="(@{cE}**@{x})" disabled>

floor(x)

Rounds towards negative infinity.

<input type="hidden" name="attr_floor" value="floor(@{x})" disabled>

hypot(x, y, z, ...)

Hypotenuse: sqrt(x^2 + y^2 + z^2 + ...).

<!-- include as many values as you need -->
<input type="hidden" name="attr_hypot" value="((@{x}**2 + @{y}**2 + @{z}**2)**0.5)" disabled>

max(x, y, z, ...)

If x > y, the result is x, while if x < y, the result is y.

<input type="hidden" name="attr_max_xy" value="(((@{x} + @{y}) + abs(@{x} - @{y})) / 2)" disabled>
<input type="hidden" name="attr_max_xyz" value="(((@{max_xy} + @{z}) + abs(@{max_xy} - @{z})) / 2)" disabled>
<input type="hidden" name="attr_max_xyzw" value="(((@{max_xyz} + @{w}) + abs(@{max_xyz} - @{w})) / 2)" disabled>

min(x, y, z, ...)

If x > y, the result is y, while if x < y, the result is x.

<input type="hidden" name="attr_min_xy" value="(((@{x} + @{y}) - abs(@{x} - @{y})) / 2)" disabled>
<input type="hidden" name="attr_min_xyz" value="(((@{min_xy} + @{z}) - abs(@{min_xy} - @{z})) / 2)" disabled>
<input type="hidden" name="attr_min_xyzw" value="(((@{min_xyz} + @{w}) - abs(@{min_xyz} - @{w})) / 2)" disabled>

pow(x, y)

x^y, this is x multiplied by itself y times; fractional values for y are permissible.

<input type="number" name="attr_pow" value="(@{x}**@{y})" disabled>

round(x)

Round towards the nearest integer. If the fractional part is 0.5, it will round towards positive infinity.

<input type="hidden" name="attr_round" value="round(@{x})" disabled>

sign(x)

If x < 0, the result is -1, while if x > 0, the result is 1 and if x = 0, the result is 0. Unfortunately, because of the nature of the calculation, we cannot correctly calculate the final possibility. This works for all values of x other than 0, however.

<input type="hidden" name="attr_sign" value="(@{x} / abs(@{x}))" disabled>

sqrt(x)

Square root: sqrt(x)^2 = x.

<input type="hidden" name="attr_sqrt" value="(@{x}**0.5)" disabled>

trunc(x)

Round towards 0.

<input type="hidden" name="attr_trunc" value="(@{sign} * floor(abs(@{x})))" disabled>

Trigonometric Functions

Trigonometric functions deal with angles and the relations between the sides of a triangle.

*acos(x)

Inverse function of cos; acos(cos(x)) = x, and if abs(x) <= 1, cos(acos(x)) = x.

<input type="hidden" name="attr_acos" value="(@{cPI} / 2 - @{asin})" disabled>

*acosh(x)

Hyperbolic arccosine.

Note: See log(x) for the definition of @{log_2x}

<input type="hidden" name="attr_acosh" value="(@{log_2x} - (1 / (4 * @{x}**2) + 3 / (32 * @{x}**4) + 15 / (288 * @{x}**6) + 105 / (384 * @{x}**8)))" disabled>

*asin(x)

Inverse function of sin; asin(sin(x)) = x, and if abs(x) <= 1, sin(asin(x)) = x.

<input type="hidden" name="attr_asin" value="(@{x} + @{x}**3 / 6 + (3 * @{x}**5) / 40 + (15 * @{x}**7) / 336)" disabled>

*asinh(x)

Hyperbolic arcsine.

<input type="hidden" name="attr_asinh" value="(@{x} - @{x}**3 / 6 + 3 * @{x}**5 / 40 - 15 * @{x}**7 / 336)" disabled>

*atan(x)

Inverse function of tan; atan(tan(x)) = x = tan(atan(x)).

<input type="hidden" name="attr_atan" value="(@{x} - @{x}**3 / 3 + @{x}**5 / 5 - @{x}**7 / 7)" disabled>

*atanh(x)

Hyperbolic arctangent.

<input type="hidden" name="attr_atan" value="(@{x} + @{x}**3 / 3 + @{x}**5 / 5 + @{x}**7 / 7)" disabled>

*atan2(y, x)

The same as atan(y / x), although the actual Math library function gracefully handles x = 0.

<input type="hidden" name="attr_atan2" value="((@{y} / @{x}) - (@{y} / @{x})**3 / 3 + (@{y} / @{x})**5 / 5 - (@{y} / @{x})**7 / 7)" disabled>

*cos(x)

The ratio of the adjacent side of a triganle from the given angle (on a right triangle) to the hypotenuse.

<input type="hidden" name="attr_cos" value="(1 - @{x}**2 / 2 + @{x}**4 / 24 - @{x}**6 / 720 + @{x}**8 / 40320)" disabled>

*cosh(x)

Hyperbolic cosine.

<input type="hidden" name="attr_cosh" value="(1 + @{x}**2 / 2 + @{x}**4 / 24 + @{x}**6 / 720 + @{x}**8 / 40320)" disabled>

*sin(x)

The ratio of the opposite side of a triangle from the given angle (on a right triangle) to the hypotenuse.

<input type="hidden" name="attr_sin" value="(@{x} - @{x}**3 / 6 + @{x}**5 / 120 - @{x}**7 / 5040)" disabled>

*sinh(x)

Hyperbolic sine.

<input type="hidden" name="attr_sinh" value="(@{x} + @{x}**3 / 6 + @{x}**5 / 120 + @{x}**7 / 5040)" disabled>

*tan(x)

The ratio of the opposite side of a triangle from the given angle (on a right triangle) to the adjacent side.

<input type="hidden" name="attr_tan" value="(@{sin} / @{cos})" disabled>

*tanh(x)

Hyperbolic tangent.

<input type="hidden" name="attr_tanh" value="(@{sinh} / @{cosh})" disabled>

Other Transcendental Functions

Transcendental functions cannot be expressed with a finite number of algebraic operations. The trigonometric functions are transcendental as well.

*log(x)

Natural logarithm (log base E) of x.

<input type="hidden" name="attr_log" value="(@{x} - @{x}**2 / 2 + @{x}**3 / 3 - @{x}**4 / 4 + @{x}**5 / 5 - @{x}**6 / 6 + @{x}**7 / 7)" disabled>
<!-- used for acosh, above -->
<input type="hidden" name="attr_log_2x" value="(@{cLN2} + @{log})" disabled>

*log1p(x)

log(1 + x)

<input type="hidden" name="attr_log1p" value="((1 + @{x}) - (1 + @{x})**2 / 2 + (1 + @{x})**3 / 3 - (1 + @{x})**4 / 4 + (1 + @{x})**5 / 5 - (1 + @{x})**6 / 6 + (1 + @{x})**7 / 7)" disabled>

*log10(x)

Log base 10 of x.

<input type="hidden" name="attr_log10" value="(@{log} / @{cLN10})" disabled>

*log2(x)

Log base 2 of x.

<input type="hidden" name="attr_log2" value="(@{log} / @{cLN2})" disabled>

Other Functions

The following functions don't really have a mathematical categorization.

*clz32(x)

The number of leading zero bits in a 32-bit number. For example, the number 64 is represented in binary as 00000000000000000000000001000000, so clz32(64) = 25.

<input type="hidden" name="attr_clz32" value="(32 - ceil(@{log1p} / @{cLN2}))" disabled>

Impossible to Implement

Some functions cannot be implemented with autocalc fields.

fround(x)

Rounds a number to the nearest 32-bit representable floating point number.

imul(x, y)

Perform 32-bit multiplication. This is functionally equivalent to trunc(x * y), except when large numbers get involved.

random()

Generate a random number in the range [0, 1). While this can't be done with autocalc fields, you can roll dice!