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Speed up rendering by not using alpha

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This commit is contained in:
Andreas Hocevar
2019-10-30 14:36:23 +01:00
parent 7097a4c6ba
commit 4b13c6dae0
2 changed files with 13 additions and 13 deletions
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16
src/ol/render/canvas/hitdetect.js
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@@ -62,7 +62,10 @@ export function createHitDetectionImageData(size, transforms, features, styleFun
const image = originalStyle.getImage();
if (image) {
const imgSize = image.getImageSize();
const imgContext = createCanvasContext2D(imgSize[0], imgSize[1]);
const canvas = document.createElement('canvas');
canvas.width = imgSize[0];
canvas.height = imgSize[1];
const imgContext = canvas.getContext('2d', {alpha: false});
imgContext.fillStyle = color;
const img = imgContext.canvas;
imgContext.fillRect(0, 0, img.width, img.height);
@@ -133,13 +136,10 @@ export function hitDetect(pixel, features, imageData) {
const r = imageData.data[index];
const g = imageData.data[index + 1];
const b = imageData.data[index + 2];
const a = imageData.data[index + 3];
if (a === 255) {
const i = b + (256 * (g + (256 * r)));
const indexFactor = Math.ceil((256 * 256 * 256) / features.length);
if (i % indexFactor === 0) {
resultFeatures.push(features[i / indexFactor]);
}
const i = b + (256 * (g + (256 * r)));
const indexFactor = Math.ceil((256 * 256 * 256) / features.length);
if (i % indexFactor === 0) {
resultFeatures.push(features[i / indexFactor]);
}
}
return resultFeatures;