初始化

src/utils/image/transform.ts

@@ -0,0 +1,41 @@
+import type { CropRect, TransformOptions } from './types'
+/**
+ * 裁剪 / 旋转 / 翻转：canvas 变换矩阵一次性重绘，全部基于源位图（非截屏，保画质）
+ */
+import { beginDraw, exportFile, loadImage, typeByExt } from './core'
+import { resultName } from './task'
+
+/** 裁剪：rect 为源图像素坐标 */
+export async function cropImage(
+  src: string,
+  rect: CropRect,
+): Promise<{ path: string, name: string }> {
+  const { img } = await loadImage(src)
+  const type = typeByExt(src)
+  const { ctx } = beginDraw(rect.width, rect.height, type === 'jpg')
+  ctx.drawImage(img as CanvasImageSource, rect.x, rect.y, rect.width, rect.height, 0, 0, rect.width, rect.height)
+  const path = await exportFile(type, 0.92)
+  return { path, name: resultName(src, 'crop', type) }
+}
+
+/** 旋转（90° 步进顺时针）+ 镜像 */
+export async function transformImage(
+  src: string,
+  opts: TransformOptions,
+): Promise<{ path: string, name: string }> {
+  const { img, width, height } = await loadImage(src)
+  const rotate = opts.rotate ?? 0
+  const swap = rotate === 90 || rotate === 270
+  const outW = swap ? height : width
+  const outH = swap ? width : height
+  const type = typeByExt(src)
+  const { ctx } = beginDraw(outW, outH, type === 'jpg')
+  ctx.save()
+  ctx.translate(outW / 2, outH / 2)
+  ctx.rotate((rotate * Math.PI) / 180)
+  ctx.scale(opts.flipH ? -1 : 1, opts.flipV ? -1 : 1)
+  ctx.drawImage(img as CanvasImageSource, -width / 2, -height / 2)
+  ctx.restore()
+  const path = await exportFile(type, 0.92)
+  return { path, name: resultName(src, 'transform', type) }
+}