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Load wasm module

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Surma
2019-01-24 15:21:34 -05:00
parent a676e1a2e9
commit 2412e925ba
1 changed files with 27 additions and 70 deletions
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97
src/codecs/rotate/processor.ts
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@@ -1,73 +1,30 @@
import { RotateOptions } from './processor-meta';
import wasmUrl from '../../../codecs/rotate/rotate.wasm';
import { RotateOptions, RotateModuleInstance } from './processor-meta';
export function rotate(data: ImageData, opts: RotateOptions): ImageData {
const { rotate } = opts;
const flipDimensions = rotate % 180 !== 0;
const { width: inputWidth, height: inputHeight } = data;
const outputWidth = flipDimensions ? inputHeight : inputWidth;
const outputHeight = flipDimensions ? inputWidth : inputHeight;
const out = new ImageData(outputWidth, outputHeight);
let i = 0;
export async function rotate(
data: ImageData,
opts: RotateOptions,
): Promise<ImageData> {
const flipDimensions = opts.rotate % 180 !== 0;
// Number of wasm memory pages (á 64KiB) needed to store the image twice.
const bytesPerImage = data.width * data.height * 4;
const numPagesNeeded = Math.ceil(bytesPerImage * 2 / (64 * 1024));
// const memory = new Uint8ClampedArray(data.data.length * 2);
// const memory = new WebAssembly.Memory({
// initial: Math.ceil(data.width * data.height * 4 * 2 / (64 * 1024)),
// });
const { instance } = (await (WebAssembly as any).instantiateStreaming(
fetch(wasmUrl),
)) as { instance: RotateModuleInstance };
// In the straight-copy case, d1 is x, d2 is y.
// x starts at 0 and increases.
// y starts at 0 and increases.
let d1Start = 0;
let d1Limit = inputWidth;
let d1Advance = 1;
let d1Multiplier = 1;
let d2Start = 0;
let d2Limit = inputHeight;
let d2Advance = 1;
let d2Multiplier = inputWidth;
if (rotate === 90) {
// d1 is y, d2 is x.
// y starts at its max value and decreases.
// x starts at 0 and increases.
d1Start = inputHeight - 1;
d1Limit = inputHeight;
d1Advance = -1;
d1Multiplier = inputWidth;
d2Start = 0;
d2Limit = inputWidth;
d2Advance = 1;
d2Multiplier = 1;
} else if (rotate === 180) {
// d1 is x, d2 is y.
// x starts at its max and decreases.
// y starts at its max and decreases.
d1Start = inputWidth - 1;
d1Limit = inputWidth;
d1Advance = -1;
d1Multiplier = 1;
d2Start = inputHeight - 1;
d2Limit = inputHeight;
d2Advance = -1;
d2Multiplier = inputWidth;
} else if (rotate === 270) {
// d1 is y, d2 is x.
// y starts at 0 and increases.
// x starts at its max and decreases.
d1Start = 0;
d1Limit = inputHeight;
d1Advance = 1;
d1Multiplier = inputWidth;
d2Start = inputWidth - 1;
d2Limit = inputWidth;
d2Advance = -1;
d2Multiplier = 1;
}
const inB = new Uint32Array(data.data.buffer);
const outB = new Uint32Array(out.data.buffer);
for (let d2 = d2Start; d2 >= 0 && d2 < d2Limit; d2 += d2Advance) {
for (let d1 = d1Start; d1 >= 0 && d1 < d1Limit; d1 += d1Advance) {
const start = ((d1 * d1Multiplier) + (d2 * d2Multiplier));
outB[i] = inB[start];
i += 1;
}
}
return out;
instance.exports.memory.grow(numPagesNeeded);
const view = new Uint8ClampedArray(instance.exports.memory.buffer);
view.set(data.data);
(self as any).instance = instance;
instance.exports.rotate(data.width, data.height, opts.rotate);
return new ImageData(
view.slice(bytesPerImage, bytesPerImage * 2),
flipDimensions ? data.height : data.width,
flipDimensions ? data.width : data.height,
);
}