feat(归并文件): 归并文件下沉通用能力

ofdgo_raster_image.go

@@ -16,16 +16,11 @@ package ofdgo
 
 import (
 	"image"
-	"math"
 
 	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"golang.org/x/image/draw"
-	"golang.org/x/image/math/f64"
 )
 
-// rasterScaleBufferLimit 限制整像素缩放器的浮点中间缓冲，超出时使用逐行采样
-const rasterScaleBufferLimit = 8 << 20
-
 // 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
@@ -38,56 +33,13 @@ func (p *RasterPage) PixelTransform(m RasterMatrix, height int) RasterMatrix {
 	return m
 }
 
-// drawRasterImage 按页面变换对图像执行高质量采样
-// 入参: dst 目标图像, src 源图像, m 像素坐标变换
-func drawRasterImage(dst draw.Image, src image.Image, m RasterMatrix) {
-	drawRasterImagePixels(dst, src, m, draw.Over)
-}
-
-// drawRasterImagePixels 对轴向缩小使用可分离采样，其余变换保留通用路径
-// 入参: dst 目标图像, src 源图像, m 像素变换, op 合成操作
-func drawRasterImagePixels(dst draw.Image, src image.Image, m RasterMatrix, op draw.Op) {
-	b := src.Bounds()
-	if dr, ok := rasterScaleBounds(b, m); ok {
-		if dr.Intersect(dst.Bounds()).Empty() {
-			return
-		}
-		draw.CatmullRom.Scale(dst, dr, src, b, op, nil)
-		return
-	}
-	if drawRasterAxisImage(dst, src, m, op) {
-		return
-	}
-	draw.CatmullRom.Transform(dst, f64.Aff3{m[0], m[2], m[4], m[1], m[3], m[5]}, src, b, op, nil)
-}
-
-// rasterScaleBounds 检查变换是否可无几何取整地使用缩放器，并限制其中间缓冲
-// 入参: b 源边界, m 像素变换
-// 返回: image.Rectangle 缩放边界, bool 是否适用
-func rasterScaleBounds(b image.Rectangle, m RasterMatrix) (image.Rectangle, bool) {
-	if b.Empty() || m[1] != 0 || m[2] != 0 || m[0] <= 0 || m[0] > 1 || m[3] <= 0 || m[3] > 1 || m[0] == 1 && m[3] == 1 {
-		return image.Rectangle{}, false
-	}
-	x0, y0 := float64(m[0]*float64(b.Min.X))+m[4], float64(m[3]*float64(b.Min.Y))+m[5]
-	x1, y1 := float64(m[0]*float64(b.Max.X))+m[4], float64(m[3]*float64(b.Max.Y))+m[5]
-	for _, v := range [4]float64{x0, y0, x1, y1} {
-		if v != math.Floor(v) || v < math.MinInt32 || v > math.MaxInt32 {
-			return image.Rectangle{}, false
-		}
-	}
-	if x1 <= x0 || y1 <= y0 || b.Dx() > math.MaxInt32 || b.Dy() > math.MaxInt32 || (x1-x0)*float64(b.Dy()) > rasterScaleBufferLimit/32 {
-		return image.Rectangle{}, false
-	}
-	return image.Rect(int(x0), int(y0), int(x1), int(y1)), true
-}
-
 // 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 {
-		drawRasterImage(dst, src, m)
+		baseimage.DrawPixels(dst, src, m, draw.Over)
 		return nil
 	}
 	mask, err := rasterClipMask(backend, page, command.Clip, cache)
@@ -97,31 +49,12 @@ func drawRasterImageCommand(backend RasterBackend, page *RasterPage, dst draw.Im
 	if mask.Rect.Empty() {
 		return nil
 	}
-	bounds := mask.Rect.Intersect(dst.Bounds()).Intersect(rasterImageBounds(src.Bounds(), m, dst.Bounds()))
+	bounds := mask.Rect.Intersect(dst.Bounds()).Intersect(baseimage.TransformBounds(src.Bounds(), m, dst.Bounds()))
 	if bounds.Empty() {
 		return nil
 	}
 	layer := image.NewRGBA64(bounds)
-	drawRasterImagePixels(layer, baseimage.PixelSource(src), m, draw.Src)
+	baseimage.DrawPixels(layer, baseimage.PixelSource(src), m, draw.Src)
 	draw.DrawMask(dst, bounds, layer, bounds.Min, mask, bounds.Min, draw.Over)
 	return nil
 }
-
-// rasterImageBounds 计算采样器可能写入的像素范围，并在整数转换前裁至目标边界
-// 入参: source 原始像素边界, m 像素变换, target 目标边界
-// 返回: image.Rectangle 受影响的目标像素区域
-func rasterImageBounds(source image.Rectangle, m RasterMatrix, target image.Rectangle) image.Rectangle {
-	minX, minY, maxX, maxY := math.Inf(1), math.Inf(1), math.Inf(-1), math.Inf(-1)
-	for _, p := range [4]image.Point{source.Min, {X: source.Max.X, Y: source.Min.Y}, {X: source.Min.X, Y: source.Max.Y}, source.Max} {
-		x := math.Floor(float64(m[0]*float64(p.X)) + float64(m[2]*float64(p.Y)) + m[4])
-		y := math.Floor(float64(m[1]*float64(p.X)) + float64(m[3]*float64(p.Y)) + m[5])
-		minX, minY = math.Min(minX, x), math.Min(minY, y)
-		maxX, maxY = math.Max(maxX, x+1), math.Max(maxY, y+1)
-	}
-	minX, minY = math.Max(minX, float64(target.Min.X)), math.Max(minY, float64(target.Min.Y))
-	maxX, maxY = math.Min(maxX, float64(target.Max.X)), math.Min(maxY, float64(target.Max.Y))
-	if minX >= maxX || minY >= maxY {
-		return image.Rectangle{}
-	}
-	return image.Rect(int(minX), int(minY), int(maxX), int(maxY))
-}