pdf.js.mirror/web/text_layer_builder.css
Nicolò Ribaudo eb2b7c2c86
Move text layer scaling logic to CSS
This commit moves all the logic to scale up&down `<span>`s in the text
layer, introduced in #18283, to CSS.

The motivation for this change is that #18283 is still not enough for
all cases. That PR fixed the problem in Chrome&Firefox desktop, which
allow users to set an actual minimum font size in the browser settings.
However, other browsers (e.g. the Chrome-based WebView on Android) have
more complex logic and they scale up small text rather than simply
applying a minimum.

A workaround for that behavior is probably out of scope for PDF.js
itself as it only affects not officially supported platforms. However,
having access to the actual expected font height (through
`--font-height`) allows embedders of PDF.js to implement a workaround by
themselves.
2025-12-09 13:12:20 +01:00

148 lines
3.7 KiB
CSS

/* Copyright 2014 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
.textLayer {
position: absolute;
text-align: initial;
inset: 0;
overflow: clip;
opacity: 1;
line-height: 1;
text-size-adjust: none;
forced-color-adjust: none;
transform-origin: 0 0;
caret-color: CanvasText;
z-index: 0;
&.highlighting {
touch-action: none;
}
:is(span, br) {
color: transparent;
position: absolute;
white-space: pre;
cursor: text;
transform-origin: 0% 0%;
}
/* We multiply the font size by --min-font-size, and then scale the text
* elements by 1/--min-font-size. This allows us to effectively ignore the
* minimum font size enforced by the browser, so that the text layer <span>s
* can always match the size of the text in the canvas. */
--min-font-size: 1;
--text-scale-factor: calc(var(--total-scale-factor) * var(--min-font-size));
--min-font-size-inv: calc(1 / var(--min-font-size));
> :not(.markedContent),
.markedContent span:not(.markedContent) {
z-index: 1;
--font-height: 0; /* set by text_layer.js */
font-size: calc(var(--text-scale-factor) * var(--font-height));
--scale-x: 1;
--rotate: 0deg;
transform: rotate(var(--rotate)) scaleX(var(--scale-x))
scale(var(--min-font-size-inv));
}
/* Only necessary in Google Chrome, see issue 14205, and most unfortunately
* the problem doesn't show up in "text" reference tests. */
/*#if !MOZCENTRAL*/
span.markedContent {
top: 0;
height: 0;
}
/*#endif*/
span[role="img"] {
user-select: none;
cursor: default;
}
.highlight {
--highlight-bg-color: rgb(180 0 170 / 0.25);
--highlight-selected-bg-color: rgb(0 100 0 / 0.25);
--highlight-backdrop-filter: none;
--highlight-selected-backdrop-filter: none;
@media screen and (forced-colors: active) {
--highlight-bg-color: transparent;
--highlight-selected-bg-color: transparent;
--highlight-backdrop-filter: var(--hcm-highlight-filter);
--highlight-selected-backdrop-filter: var(
--hcm-highlight-selected-filter
);
}
margin: -1px;
padding: 1px;
background-color: var(--highlight-bg-color);
backdrop-filter: var(--highlight-backdrop-filter);
border-radius: 4px;
&.appended {
position: initial;
}
&.begin {
border-radius: 4px 0 0 4px;
}
&.end {
border-radius: 0 4px 4px 0;
}
&.middle {
border-radius: 0;
}
&.selected {
background-color: var(--highlight-selected-bg-color);
backdrop-filter: var(--highlight-selected-backdrop-filter);
}
}
::selection {
/* stylelint-disable declaration-block-no-duplicate-properties */
/*#if !MOZCENTRAL*/
background: rgba(0 0 255 / 0.25);
/*#endif*/
/* stylelint-enable declaration-block-no-duplicate-properties */
background: color-mix(in srgb, AccentColor, transparent 75%);
}
/* Avoids https://github.com/mozilla/pdf.js/issues/13840 in Chrome */
/*#if !MOZCENTRAL*/
br::selection {
background: transparent;
}
/*#endif*/
.endOfContent {
display: block;
position: absolute;
inset: 100% 0 0;
z-index: 0;
cursor: default;
user-select: none;
}
&.selecting .endOfContent {
top: 0;
}
}