diff --git a/go.mod b/go.mod index 4ceb63e..b851c06 100644 --- a/go.mod +++ b/go.mod @@ -9,7 +9,7 @@ require ( github.com/tdewolff/canvas v0.0.0-20260923214215-09804640d00c github.com/tdewolff/font v0.0.0-20260913163313-54f98bb59ee6 github.com/xiaoqidun/jbig2 v1.1.1 - github.com/xiaoqidun/pdfgo v0.0.0-20260927114248-f2deafc71b89 + github.com/xiaoqidun/pdfgo v0.0.0-20260927123406-320d8b5546b5 golang.org/x/crypto v0.57.0 golang.org/x/image v0.46.0 golang.org/x/text v0.42.0 diff --git a/go.sum b/go.sum index 5bf1f31..863fc81 100644 --- a/go.sum +++ b/go.sum @@ -62,8 +62,8 @@ github.com/tdewolff/test v1.0.12 h1:7F21DqIajswxuche0geHdrUZRCWE4oko4b7bcmkkrxk= github.com/tdewolff/test v1.0.12/go.mod h1:XPuWBzvdUzhCuxWO1ojpXsyzsA5bFoS3tO/Q3kFuTG8= github.com/xiaoqidun/jbig2 v1.1.1 h1:SjliS9ZO0e9HX5oYUfBuXrfFsXhWricrSz+XY4zORDI= github.com/xiaoqidun/jbig2 v1.1.1/go.mod h1:8QonVWtENmh2kc6l+leqeGl7psb79DWlHDkCpdChjfQ= -github.com/xiaoqidun/pdfgo v0.0.0-20260927114248-f2deafc71b89 h1:pdnJkITNBORnYyoqU0u9MDHpjwnALvkiBS8cdJFRTRg= -github.com/xiaoqidun/pdfgo v0.0.0-20260927114248-f2deafc71b89/go.mod h1:4Pf0JO0BEf1uzRY+uZjlMjN/OPn3PYa0YMi6cqPPTLQ= +github.com/xiaoqidun/pdfgo v0.0.0-20260927123406-320d8b5546b5 h1:FyW2HSyxcrf33xo3F1eKVZmlizgpxML2H+qn63yXcDI= +github.com/xiaoqidun/pdfgo v0.0.0-20260927123406-320d8b5546b5/go.mod h1:4Pf0JO0BEf1uzRY+uZjlMjN/OPn3PYa0YMi6cqPPTLQ= github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU= github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E= github.com/yuin/goldmark v1.8.5 h1:r6N5afV5qj/5S4UTch8agZHJ8UxNCMwX7WjkkJam2NA= diff --git a/ofdgo_image.go b/ofdgo_image.go index 6b7aa4c..19f874e 100644 --- a/ofdgo_image.go +++ b/ofdgo_image.go @@ -426,6 +426,9 @@ func imageWithTransparentEdge(img image.Image) (image.Image, int) { if opaque, ok := source.(interface{ Opaque() bool }); ok && opaque.Opaque() { return img, 0 } + if model := source.ColorModel(); model == color.NRGBA64Model || model == color.RGBA64Model || model == color.Alpha16Model || model == color.Gray16Model { + return imageWithTransparentEdge64(img, source) + } hasZero, hasVisible := false, false src, ok := source.(*image.NRGBA) if ok { @@ -510,3 +513,81 @@ func (s *transparentEdgeImage) RGBA64At(x, y int) color.RGBA64 { r, g, b, a := s.NRGBAAt(x, y).RGBA() return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)} } + +// imageWithTransparentEdge64 保留十六位颜色和透明度,不经八位图像中转 +// 入参: original 原始图像, source 已解码的像素源 +// 返回: image.Image 边缘处理结果, int 补齐像素数 +func imageWithTransparentEdge64(original, source image.Image) (image.Image, int) { + bounds := source.Bounds() + hasZero, hasVisible := false, false + for y := bounds.Min.Y; y < bounds.Max.Y && !(hasZero && hasVisible); y++ { + for x := bounds.Min.X; x < bounds.Max.X; x++ { + _, _, _, a := source.At(x, y).RGBA() + if a == 0 { + hasZero = true + } else { + hasVisible = true + } + if hasZero && hasVisible { + break + } + } + } + if !hasZero || !hasVisible { + return original, 0 + } + return &transparentEdgeImage64{source: source, rect: image.Rect(0, 0, bounds.Dx()+2, bounds.Dy()+2)}, 1 +} + +// transparentEdgeImage64 按需补齐十六位像素边缘,保留原始只读图像 +type transparentEdgeImage64 struct { + source image.Image + rect image.Rectangle +} + +// Bounds 返回含采样边距的图像边界 +// 返回: image.Rectangle 图像边界 +func (s *transparentEdgeImage64) Bounds() image.Rectangle { return s.rect } + +// ColorModel 返回十六位非预乘颜色模型 +// 返回: color.Model 颜色模型 +func (s *transparentEdgeImage64) ColorModel() color.Model { return color.NRGBA64Model } + +// At 读取十六位原始颜色,透明邻域使用最小非零透明度保留边缘颜色 +// 入参: x 横向坐标, y 纵向坐标 +// 返回: color.Color 非预乘颜色 +func (s *transparentEdgeImage64) At(x, y int) color.Color { + if !image.Pt(x, y).In(s.rect) { + return color.NRGBA64{} + } + b := s.source.Bounds() + sx, sy := b.Min.X+min(max(x-1, 0), b.Dx()-1), b.Min.Y+min(max(y-1, 0), b.Dy()-1) + c := color.NRGBA64Model.Convert(s.source.At(sx, sy)).(color.NRGBA64) + if c.A == 0 { + var best color.NRGBA64 + for ny := max(sy-1, b.Min.Y); ny < min(sy+2, b.Max.Y); ny++ { + for nx := max(sx-1, b.Min.X); nx < min(sx+2, b.Max.X); nx++ { + v := color.NRGBA64Model.Convert(s.source.At(nx, ny)).(color.NRGBA64) + if v.A > best.A { + best = v + } + } + } + if best.A != 0 { + best.A = 1 + c = best + } + } + if x == 0 || y == 0 || x == s.rect.Max.X-1 || y == s.rect.Max.Y-1 { + c.A = 1 + } + return c +} + +// RGBA64At 返回保留原采样精度的预乘颜色 +// 入参: x 横向坐标, y 纵向坐标 +// 返回: color.RGBA64 预乘颜色 +func (s *transparentEdgeImage64) RGBA64At(x, y int) color.RGBA64 { + r, g, b, a := s.At(x, y).RGBA() + return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)} +} diff --git a/ofdgo_raster_image.go b/ofdgo_raster_image.go index 152660a..e965fd5 100644 --- a/ofdgo_raster_image.go +++ b/ofdgo_raster_image.go @@ -25,7 +25,41 @@ import ( // 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) { - draw.CatmullRom.Transform(dst, f64.Aff3{m[0], m[2], m[4], m[1], m[3], m[5]}, src, src.Bounds(), draw.Over, nil) + drawRasterImagePixels(dst, src, m, draw.Over) +} + +// drawRasterImagePixels 对整像素边界的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 + } + 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,并避开其整数溢出范围 +// 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()) > float64(min(math.MaxInt32, int(^uint(0)>>1)/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 @@ -49,7 +83,7 @@ func drawRasterImageCommand(backend RasterBackend, page *RasterPage, dst draw.Im return nil } layer := image.NewRGBA64(bounds) - draw.CatmullRom.Transform(layer, f64.Aff3{m[0], m[2], m[4], m[1], m[3], m[5]}, imagePixelSource(src), src.Bounds(), draw.Src, nil) + drawRasterImagePixels(layer, imagePixelSource(src), m, draw.Src) draw.DrawMask(dst, bounds, layer, bounds.Min, mask, bounds.Min, draw.Over) return nil }