Fix buffer size/offset calculations in rotate/processor.ts

This commit is contained in:
Joachim Viide
2019-02-12 00:12:04 +02:00
parent ece3fa12b4
commit 9ed3b4f11e

View File

@ -11,7 +11,7 @@ export async function rotate(
// 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) + 4);
const numPagesNeeded = Math.ceil((bytesPerImage * 2 + 4) / (64 * 1024));
// Only count full pages, just to be safe.
const numPagesAvailable = Math.floor(instance.exports.memory.buffer.byteLength / (64 * 1024));
const additionalPagesToAllocate = numPagesNeeded - numPagesAvailable;
@ -20,13 +20,13 @@ export async function rotate(
instance.exports.memory.grow(additionalPagesToAllocate);
}
const view = new Uint8ClampedArray(instance.exports.memory.buffer);
view.set(data.data);
view.set(data.data, 4);
instance.exports.rotate(data.width, data.height, opts.rotate);
const flipDimensions = opts.rotate % 180 !== 0;
return new ImageData(
view.slice(bytesPerImage, bytesPerImage * 2),
view.slice(bytesPerImage + 4, bytesPerImage * 2 + 4),
flipDimensions ? data.height : data.width,
flipDimensions ? data.width : data.height,
);