feat(归并文件): 归并根包文件，保持接口不变

ofdgo_raster_clip.go

@@ -23,6 +23,7 @@ import (
 	"math"
 
 	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
+	"golang.org/x/image/draw"
 )
 
 // rasterClipKey 区分页面尺寸、分辨率和裁剪路径
@@ -114,3 +115,41 @@ func rasterClipMask(backend RasterBackend, page *RasterPage, path []RasterSegmen
 	cache.put(key, mask, len(mask.Pix)+256)
 	return mask, nil
 }
+
+// PixelTransform 将页面毫米变换转换为像素变换，保留尺寸取整后的原点位置
+// 入参: m 局部到页面变换, height 目标像素高度
+// 返回: RasterMatrix 局部到像素变换
+func (p *RasterPage) PixelTransform(m RasterMatrix, height int) RasterMatrix {
+	scale := p.DPI / 25.4
+	for i := range m {
+		m[i] *= scale
+	}
+	m[5] += float64(height) - p.Height*scale
+	return m
+}
+
+// drawRasterImageCommand 使用当前后端生成裁剪蒙版，共用高质量图像采样
+// 入参: backend 当前后端, page 页面, dst 目标图像, src 原始图像, command 图像指令, cache 蒙版缓存
+// 返回: error 裁剪绘制错误
+func drawRasterImageCommand(backend RasterBackend, page *RasterPage, dst draw.Image, src image.Image, command RasterCommand, cache *renderCache[[32]byte, *image.Alpha]) error {
+	m := page.PixelTransform(command.Transform, dst.Bounds().Dy())
+	if command.Clip == nil {
+		baseimage.DrawPixels(dst, src, m, draw.Over)
+		return nil
+	}
+	mask, err := rasterClipMask(backend, page, command.Clip, cache)
+	if err != nil {
+		return err
+	}
+	if mask.Rect.Empty() {
+		return nil
+	}
+	bounds := mask.Rect.Intersect(dst.Bounds()).Intersect(baseimage.TransformBounds(src.Bounds(), m, dst.Bounds()))
+	if bounds.Empty() {
+		return nil
+	}
+	layer := image.NewRGBA64(bounds)
+	baseimage.DrawPixels(layer, baseimage.PixelSource(src), m, draw.Src)
+	draw.DrawMask(dst, bounds, layer, bounds.Min, mask, bounds.Min, draw.Over)
+	return nil
+}