feat(归并文件): 归并根包文件

ofdgo_renderer_output_canvas.go

@@ -17,9 +17,14 @@ package ofdgo
 import (
 	"bufio"
 	"bytes"
+	"compress/zlib"
+	"context"
+	"encoding/ascii85"
 	"fmt"
 	"image"
+	"image/jpeg"
 	"io"
+	"math"
 	"strconv"
 
 	"github.com/tdewolff/canvas"
@@ -35,6 +40,15 @@ type canvasEPSWriter struct {
 	io.Writer
 }
 
+// epsImageRenderer 在EPS输出端优化图片，不修改页面及渲染缓存
+type epsImageRenderer struct {
+	*ps.PS
+	writer  io.Writer
+	options CompressionOptions
+	ctx     context.Context
+	err     error
+}
+
 // RenderSVG 使用canvas输出SVG，按模式保留资源和对象分组
 // 入参: r 渲染器, page 页面内容, writer 输出流, mode 资源模式
 // 返回: SVGResources 外部资源, error 错误信息
@@ -234,3 +248,101 @@ func (CanvasBackend) RenderPDF(r *Renderer, pages []RenderDocumentPage, writer i
 	}
 	return renderer.writePDF(r.outputContext(), data, writer, options)
 }
+
+// RenderImage 写出Flate或更小的JPEG图片，保留显示尺寸与变换
+// 入参: img 图片, matrix 绘制变换
+func (r *epsImageRenderer) RenderImage(img image.Image, matrix canvas.Matrix) {
+	if r.err != nil {
+		return
+	}
+	if dpi := r.options.ImageDPI(); dpi > 0 {
+		original := img.Bounds().Size()
+		target := compressionImageSize(math.Hypot(matrix[0][0], matrix[1][0])*float64(original.X), math.Hypot(matrix[0][1], matrix[1][1])*float64(original.Y), dpi)
+		img, r.err = pdfgo.ResizeImage(r.ctx, img, target)
+		if r.err != nil {
+			return
+		}
+		size := img.Bounds().Size()
+		if size.X > 0 && size.Y > 0 {
+			matrix = matrix.Scale(float64(original.X)/float64(size.X), float64(original.Y)/float64(size.Y))
+		}
+	}
+	bounds := img.Bounds()
+	width, height := bounds.Dx(), bounds.Dy()
+	pixels := make([]byte, width*3)
+	var encoded bytes.Buffer
+	compressor, _ := zlib.NewWriterLevel(&encoded, zlib.BestCompression)
+	opaque := true
+	native, _ := img.(image.RGBA64Image)
+	for y := 0; y < height; y++ {
+		if r.err = r.ctx.Err(); r.err != nil {
+			return
+		}
+		clear(pixels)
+		for x := 0; x < width; x++ {
+			if x&4095 == 0 {
+				if r.err = r.ctx.Err(); r.err != nil {
+					return
+				}
+			}
+			var red, green, blue, alpha uint32
+			if native != nil {
+				pixel := native.RGBA64At(bounds.Min.X+x, bounds.Min.Y+y)
+				red, green, blue, alpha = uint32(pixel.R), uint32(pixel.G), uint32(pixel.B), uint32(pixel.A)
+			} else {
+				red, green, blue, alpha = img.At(bounds.Min.X+x, bounds.Min.Y+y).RGBA()
+			}
+			if alpha != 65535 {
+				opaque = false
+			}
+			if alpha == 65535 {
+				offset := x * 3
+				pixels[offset], pixels[offset+1], pixels[offset+2] = byte(red>>8), byte(green>>8), byte(blue>>8)
+			} else if alpha != 0 {
+				offset := x * 3
+				pixels[offset], pixels[offset+1], pixels[offset+2] = byte(red*65535/alpha>>8), byte(green*65535/alpha>>8), byte(blue*65535/alpha>>8)
+			}
+		}
+		if r.err = r.ctx.Err(); r.err != nil {
+			return
+		}
+		if _, r.err = compressor.Write(pixels); r.err != nil {
+			return
+		}
+	}
+	if r.err = compressor.Close(); r.err != nil {
+		return
+	}
+	data := encoded.Bytes()
+	filter := "FlateDecode"
+	if opaque && r.options.Mode == CompressionLossy {
+		var candidate bytes.Buffer
+		if r.err = jpeg.Encode(&candidate, img, &jpeg.Options{Quality: r.options.ImageQuality()}); r.err != nil {
+			return
+		}
+		optimized, err := pdfgo.OptimizeJPEG(r.ctx, candidate.Bytes())
+		if err != nil {
+			r.err = err
+			return
+		}
+		if len(optimized) < len(data) {
+			data, filter = optimized, "DCTDecode"
+		}
+	}
+	if r.err = r.ctx.Err(); r.err != nil {
+		return
+	}
+	m := matrix.Scale(float64(width), float64(height))
+	_, r.err = fmt.Fprintf(r.writer, " gsave /DeviceRGB setcolorspace [%s %s %s %s %s %s] concat <</ImageType 1 /BitsPerComponent 8 /Decode [0 1 0 1 0 1] /Interpolate true /Width %d /Height %d /ImageMatrix [%d 0 0 -%d 0 %d] /DataSource currentfile /ASCII85Decode filter /%s filter>>image\n", ofdNumber(m[0][0]), ofdNumber(m[1][0]), ofdNumber(m[0][1]), ofdNumber(m[1][1]), ofdNumber(m[0][2]), ofdNumber(m[1][2]), width, height, width, height, height, filter)
+	if r.err != nil {
+		return
+	}
+	writer := ascii85.NewEncoder(r.writer)
+	if _, r.err = writer.Write(data); r.err != nil {
+		return
+	}
+	if r.err = writer.Close(); r.err != nil {
+		return
+	}
+	_, r.err = io.WriteString(r.writer, "~>\n grestore")
+}