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Reduce the size of TextLayerRenderTask._textDivProperties in "regular" text-selection mode

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While these changes will obviously not have a significant effect on overall memory usage, it cannot hurt as far as I'm concerned. This patch makes the following changes:
 - Clear out `_textDivProperties` once rendering is done, since those properties are only necessary to keep alive when *enhanced* text-selection is being used.

 - Reduce the size of the `_textDivProperties`-entries by default, since a majority of the properties are only relevant when *enhanced* text-selection is being used.
This commit is contained in:
Jonas Jenwald 2021-09-05 12:12:34 +02:00
parent 1b20f61b56
commit 4c1b586dd2
1 changed files with 29 additions and 14 deletions
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43
src/display/text_layer.js
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@ -118,18 +118,25 @@ function getAscent(fontFamily, ctx) {
function appendText(task, geom, styles, ctx) {
// Initialize all used properties to keep the caches monomorphic.
const textDiv = document.createElement("span");
const textDivProperties = {
angle: 0,
canvasWidth: 0,
hasText: geom.str !== "",
hasEOL: geom.hasEOL,
originalTransform: null,
paddingBottom: 0,
paddingLeft: 0,
paddingRight: 0,
paddingTop: 0,
scale: 1,
};
const textDivProperties = task._enhanceTextSelection
? {
angle: 0,
canvasWidth: 0,
hasText: geom.str !== "",
hasEOL: geom.hasEOL,
originalTransform: null,
paddingBottom: 0,
paddingLeft: 0,
paddingRight: 0,
paddingTop: 0,
scale: 1,
}
: {
angle: 0,
canvasWidth: 0,
hasText: geom.str !== "",
hasEOL: geom.hasEOL,
};
task._textDivs.push(textDiv);
@ -588,6 +595,11 @@ class TextLayerRenderTask {
// Always clean-up the temporary canvas once rendering is no longer pending.
this._capability.promise
.finally(() => {
if (!this._enhanceTextSelection) {
// The `textDiv` properties are no longer needed.
this._textDivProperties = null;
}
if (this._layoutTextCtx) {
// Zeroing the width and height cause Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
@ -679,8 +691,11 @@ class TextLayerRenderTask {
const { width } = this._layoutTextCtx.measureText(textDiv.textContent);
if (width > 0) {
textDivProperties.scale = textDivProperties.canvasWidth / width;
transform = `scaleX(${textDivProperties.scale})`;
const scale = textDivProperties.canvasWidth / width;
if (this._enhanceTextSelection) {
textDivProperties.scale = scale;
}
transform = `scaleX(${scale})`;
}
}
if (textDivProperties.angle !== 0) {