Better resize methods (#498)

* Port resize to wasm

* Expose resize algorithms

* Lanczos3 working!

* lol copy paste

* Adding support for other resizers

* Don’t track generated README

* Cache wasm instance

src/codecs/resize/options.tsx

@@ -87,6 +87,10 @@ export default class ResizerOptions extends Component<Props, State> {
             onChange={this.onChange}
           >
             {isVector && <option value="vector">Vector</option>}
+            <option value="lanczos3">Lanczos3</option>
+            <option value="mitchell">Mitchell</option>
+            <option value="catrom">Catmull-Rom</option>
+            <option value="triangle">Triangle</option>
             <option value="browser-pixelated">Browser pixelated</option>
             <option value="browser-low">Browser low quality</option>
             <option value="browser-medium">Browser medium quality</option>

src/codecs/resize/processor-meta.ts

@@ -1,14 +1,19 @@
-type BitmapResizeMethods = 'browser-pixelated' | 'browser-low' | 'browser-medium' | 'browser-high';
+type BrowserResizeMethods = 'browser-pixelated' | 'browser-low' | 'browser-medium' | 'browser-high';
+type WorkerResizeMethods = 'point' | 'triangle' | 'catrom' | 'mitchell' | 'lanczos3';
 
 export interface ResizeOptions {
   width: number;
   height: number;
-  method: 'vector' | BitmapResizeMethods;
+  method: 'vector' | BrowserResizeMethods | WorkerResizeMethods;
   fitMethod: 'stretch' | 'contain';
 }
 
-export interface BitmapResizeOptions extends ResizeOptions {
-  method: BitmapResizeMethods;
+export interface BrowserResizeOptions extends ResizeOptions {
+  method: BrowserResizeMethods;
+}
+
+export interface WorkerResizeOptions extends ResizeOptions {
+  method: WorkerResizeMethods;
 }
 
 export interface VectorResizeOptions extends ResizeOptions {
@@ -21,6 +26,6 @@ export const defaultOptions: ResizeOptions = {
   width: 1,
   height: 1,
   // This will be set to 'vector' if the input is SVG.
-  method: 'browser-high',
+  method: 'lanczos3',
   fitMethod: 'stretch',
 };

src/codecs/resize/processor-sync.ts

@@ -0,0 +1,35 @@
+import { nativeResize, NativeResizeMethod, drawableToImageData } from '../../lib/util';
+import { BrowserResizeOptions, VectorResizeOptions } from './processor-meta';
+import { getContainOffsets } from './util';
+
+export function browserResize(data: ImageData, opts: BrowserResizeOptions): ImageData {
+  let sx = 0;
+  let sy = 0;
+  let sw = data.width;
+  let sh = data.height;
+
+  if (opts.fitMethod === 'contain') {
+    ({ sx, sy, sw, sh } = getContainOffsets(sw, sh, opts.width, opts.height));
+  }
+
+  return nativeResize(
+    data, sx, sy, sw, sh, opts.width, opts.height,
+    opts.method.slice('browser-'.length) as NativeResizeMethod,
+  );
+}
+
+export function vectorResize(data: HTMLImageElement, opts: VectorResizeOptions): ImageData {
+  let sx = 0;
+  let sy = 0;
+  let sw = data.width;
+  let sh = data.height;
+
+  if (opts.fitMethod === 'contain') {
+    ({ sx, sy, sw, sh } = getContainOffsets(sw, sh, opts.width, opts.height));
+  }
+
+  return drawableToImageData(data, {
+    sx, sy, sw, sh,
+    width: opts.width, height: opts.height,
+  });
+}

src/codecs/resize/processor.ts

@@ -1,49 +1,52 @@
-import { nativeResize, NativeResizeMethod, drawableToImageData } from '../../lib/util';
-import { BitmapResizeOptions, VectorResizeOptions } from './processor-meta';
+import wasmUrl from '../../../codecs/resize/pkg/resize_bg.wasm';
+import '../../../codecs/resize/pkg/resize';
+import { WorkerResizeOptions } from './processor-meta';
+import { getContainOffsets } from './util';
 
-function getContainOffsets(sw: number, sh: number, dw: number, dh: number) {
-  const currentAspect = sw / sh;
-  const endAspect = dw / dh;
-
-  if (endAspect > currentAspect) {
-    const newSh = sw / endAspect;
-    const newSy = (sh - newSh) / 2;
-    return { sw, sh: newSh, sx: 0, sy: newSy };
-  }
-
-  const newSw = sh * endAspect;
-  const newSx = (sw - newSw) / 2;
-  return { sh, sw: newSw, sx: newSx, sy: 0 };
+interface WasmBindgenExports {
+  resize: typeof import('../../../codecs/resize/pkg/resize').resize;
 }
 
-export function resize(data: ImageData, opts: BitmapResizeOptions): ImageData {
-  let sx = 0;
-  let sy = 0;
-  let sw = data.width;
-  let sh = data.height;
+type WasmBindgen = ((url: string) => Promise<void>) & WasmBindgenExports;
 
-  if (opts.fitMethod === 'contain') {
-    ({ sx, sy, sw, sh } = getContainOffsets(sw, sh, opts.width, opts.height));
+declare var wasm_bindgen: WasmBindgen;
+
+const ready = wasm_bindgen(wasmUrl);
+
+function crop(data: ImageData, sx: number, sy: number, sw: number, sh: number): ImageData {
+  const inputPixels = new Uint32Array(data.data.buffer);
+
+  // Copy within the same buffer for speed and memory efficiency.
+  for (let y = 0; y < sh; y += 1) {
+    const start = ((y + sy) * data.width) + sx;
+    inputPixels.copyWithin(y * sw, start, start + sw);
   }
 
-  return nativeResize(
-    data, sx, sy, sw, sh, opts.width, opts.height,
-    opts.method.slice('browser-'.length) as NativeResizeMethod,
+  return new ImageData(
+    new Uint8ClampedArray(inputPixels.buffer.slice(0, sw * sh * 4)),
+    sw, sh,
   );
 }
 
-export function vectorResize(data: HTMLImageElement, opts: VectorResizeOptions): ImageData {
-  let sx = 0;
-  let sy = 0;
-  let sw = data.width;
-  let sh = data.height;
+/** Resize methods by index */
+const resizeMethods: WorkerResizeOptions['method'][] = [
+  'triangle', 'catrom', 'mitchell', 'lanczos3',
+];
+
+export async function resize(data: ImageData, opts: WorkerResizeOptions): Promise<ImageData> {
+  let input = data;
 
   if (opts.fitMethod === 'contain') {
-    ({ sx, sy, sw, sh } = getContainOffsets(sw, sh, opts.width, opts.height));
+    const { sx, sy, sw, sh } = getContainOffsets(data.width, data.height, opts.width, opts.height);
+    input = crop(input, Math.round(sx), Math.round(sy), Math.round(sw), Math.round(sh));
   }
 
-  return drawableToImageData(data, {
-    sx, sy, sw, sh,
-    width: opts.width, height: opts.height,
-  });
+  await ready;
+
+  const result = wasm_bindgen.resize(
+    new Uint8Array(input.data.buffer), input.width, input.height, opts.width, opts.height,
+    resizeMethods.indexOf(opts.method),
+  );
+
+  return new ImageData(new Uint8ClampedArray(result.buffer), opts.width, opts.height);
 }

src/codecs/resize/util.ts

@@ -0,0 +1,14 @@
+export function getContainOffsets(sw: number, sh: number, dw: number, dh: number) {
+  const currentAspect = sw / sh;
+  const endAspect = dw / dh;
+
+  if (endAspect > currentAspect) {
+    const newSh = sw / endAspect;
+    const newSy = (sh - newSh) / 2;
+    return { sw, sh: newSh, sx: 0, sy: newSy };
+  }
+
+  const newSw = sh * endAspect;
+  const newSx = (sw - newSw) / 2;
+  return { sh, sw: newSw, sx: newSx, sy: 0 };
+}