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perf: cache approx line height in textwysiwg (#4651)

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Aakansha Doshi 2022-01-25 17:01:12 +05:30 committed by GitHub
parent c009e03c8e
commit abff780983
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 17 additions and 7 deletions
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8
src/element/textElement.ts
View File

@ -205,8 +205,14 @@ export const measureText = (
};
const DUMMY_TEXT = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toLocaleUpperCase();
const cacheApproxLineHeight: { [key: FontString]: number } = {};
export const getApproxLineHeight = (font: FontString) => {
return measureText(DUMMY_TEXT, font, null).height;
if (cacheApproxLineHeight[font]) {
return cacheApproxLineHeight[font];
}
cacheApproxLineHeight[font] = measureText(DUMMY_TEXT, font, null).height;
return cacheApproxLineHeight[font];
};
let canvas: HTMLCanvasElement | undefined;

16
src/element/textWysiwyg.tsx
View File

@ -102,10 +102,12 @@ export const textWysiwyg = ({
return false;
};
let originalContainerHeight: number;
let approxLineHeight = getApproxLineHeight(getFontString(element));
const updateWysiwygStyle = () => {
const updatedElement = Scene.getScene(element)?.getElement(id);
const updatedElement = Scene.getScene(element)?.getElement(
id,
) as ExcalidrawTextElement;
const approxLineHeight = getApproxLineHeight(getFontString(updatedElement));
if (updatedElement && isTextElement(updatedElement)) {
let coordX = updatedElement.x;
let coordY = updatedElement.y;
@ -128,8 +130,6 @@ export const textWysiwyg = ({
height = editorHeight;
}
if (propertiesUpdated) {
approxLineHeight = getApproxLineHeight(getFontString(updatedElement));
originalContainerHeight = container.height;
// update height of the editor after properties updated
@ -268,10 +268,14 @@ export const textWysiwyg = ({
if (onChange) {
editable.oninput = () => {
const updatedElement = Scene.getScene(element)?.getElement(
id,
) as ExcalidrawTextElement;
const font = getFontString(updatedElement);
// using scrollHeight here since we need to calculate
// number of lines so cannot use editable.style.height
// as that gets updated below
const lines = editable.scrollHeight / approxLineHeight;
const lines = editable.scrollHeight / getApproxLineHeight(font);
// auto increase height only when lines > 1 so its
// measured correctly and vertically alignes for
// first line as well as setting height to "auto"
@ -283,7 +287,7 @@ export const textWysiwyg = ({
const container = getContainerElement(element);
const actualLineCount = wrapText(
editable.value,
getFontString(element),
font,
container!.width,
).split("\n").length;