Allow default compression mode to be set. Go 1.7 introduces a new compression/flate routine that results in different compressed streams than before. Consequently, PDFs generated with go 1.7 are not generally binary-equivalent with those generated with previous versions. Turning off compression for test files removes this variability. However, it does not help with PDFs that contain images. For now, those reference PDFs have been removed to allow tests to proceed.

1 files changed, 212 insertions, 0 deletions

diff --git a/png.go b/png.go
new file mode 100644
index 0000000..854b003
--- /dev/null
+++ b/png.go
@@ -0,0 +1,212 @@
+/*
+ * Copyright (c) 2013-2016 Kurt Jung (Gmail: kurt.w.jung)
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+package gofpdf
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+func (f *Fpdf) pngColorSpace(ct byte) (colspace string, colorVal int) {
+	colorVal = 1
+	switch ct {
+	case 0, 4:
+		colspace = "DeviceGray"
+	case 2, 6:
+		colspace = "DeviceRGB"
+		colorVal = 3
+	case 3:
+		colspace = "Indexed"
+	default:
+		f.err = fmt.Errorf("unknown color type in PNG buffer: %d", ct)
+	}
+	return
+}
+
+func (f *Fpdf) parsepngstream(buf *bytes.Buffer, readdpi bool) (info *ImageInfoType) {
+	info = f.newImageInfo()
+	// 	Check signature
+	if string(buf.Next(8)) != "\x89PNG\x0d\x0a\x1a\x0a" {
+		f.err = fmt.Errorf("not a PNG buffer")
+		return
+	}
+	// Read header chunk
+	_ = buf.Next(4)
+	if string(buf.Next(4)) != "IHDR" {
+		f.err = fmt.Errorf("incorrect PNG buffer")
+		return
+	}
+	w := f.readBeInt32(buf)
+	h := f.readBeInt32(buf)
+	bpc := f.readByte(buf)
+	if bpc > 8 {
+		f.err = fmt.Errorf("16-bit depth not supported in PNG file")
+	}
+	ct := f.readByte(buf)
+	var colspace string
+	var colorVal int
+	colspace, colorVal = f.pngColorSpace(ct)
+	if f.err != nil {
+		return
+	}
+	if f.readByte(buf) != 0 {
+		f.err = fmt.Errorf("'unknown compression method in PNG buffer")
+		return
+	}
+	if f.readByte(buf) != 0 {
+		f.err = fmt.Errorf("'unknown filter method in PNG buffer")
+		return
+	}
+	if f.readByte(buf) != 0 {
+		f.err = fmt.Errorf("interlacing not supported in PNG buffer")
+		return
+	}
+	_ = buf.Next(4)
+	dp := sprintf("/Predictor 15 /Colors %d /BitsPerComponent %d /Columns %d", colorVal, bpc, w)
+	// Scan chunks looking for palette, transparency and image data
+	pal := make([]byte, 0, 32)
+	var trns []int
+	data := make([]byte, 0, 32)
+	loop := true
+	for loop {
+		n := int(f.readBeInt32(buf))
+		// dbg("Loop [%d]", n)
+		switch string(buf.Next(4)) {
+		case "PLTE":
+			// dbg("PLTE")
+			// Read palette
+			pal = buf.Next(n)
+			_ = buf.Next(4)
+		case "tRNS":
+			// dbg("tRNS")
+			// Read transparency info
+			t := buf.Next(n)
+			if ct == 0 {
+				trns = []int{int(t[1])} // ord(substr($t,1,1)));
+			} else if ct == 2 {
+				trns = []int{int(t[1]), int(t[3]), int(t[5])} // array(ord(substr($t,1,1)), ord(substr($t,3,1)), ord(substr($t,5,1)));
+			} else {
+				pos := strings.Index(string(t), "\x00")
+				if pos >= 0 {
+					trns = []int{pos} // array($pos);
+				}
+			}
+			_ = buf.Next(4)
+		case "IDAT":
+			// dbg("IDAT")
+			// Read image data block
+			data = append(data, buf.Next(n)...)
+			_ = buf.Next(4)
+		case "IEND":
+			// dbg("IEND")
+			loop = false
+		case "pHYs":
+			// dbg("pHYs")
+			// png files theoretically support different x/y dpi
+			// but we ignore files like this
+			// but if they're the same then we can stamp our info
+			// object with it
+			x := int(f.readBeInt32(buf))
+			y := int(f.readBeInt32(buf))
+			units := buf.Next(1)[0]
+			// fmt.Printf("got a pHYs block, x=%d, y=%d, u=%d, readdpi=%t\n",
+			// x, y, int(units), readdpi)
+			// only modify the info block if the user wants us to
+			if x == y && readdpi {
+				switch units {
+				// if units is 1 then measurement is px/meter
+				case 1:
+					info.dpi = float64(x) / 39.3701 // inches per meter
+				default:
+					info.dpi = float64(x)
+				}
+			}
+			_ = buf.Next(4)
+		default:
+			// dbg("default")
+			_ = buf.Next(n + 4)
+		}
+		if loop {
+			loop = n > 0
+		}
+	}
+	if colspace == "Indexed" && len(pal) == 0 {
+		f.err = fmt.Errorf("missing palette in PNG buffer")
+	}
+	info.w = float64(w)
+	info.h = float64(h)
+	info.cs = colspace
+	info.bpc = int(bpc)
+	info.f = "FlateDecode"
+	info.dp = dp
+	info.pal = pal
+	info.trns = trns
+	// dbg("ct [%d]", ct)
+	if ct >= 4 {
+		// Separate alpha and color channels
+		var err error
+		data, err = sliceUncompress(data)
+		if err != nil {
+			f.err = err
+			return
+		}
+		var color, alpha bytes.Buffer
+		if ct == 4 {
+			// Gray image
+			width := int(w)
+			height := int(h)
+			length := 2 * width
+			var pos, elPos int
+			for i := 0; i < height; i++ {
+				pos = (1 + length) * i
+				color.WriteByte(data[pos])
+				alpha.WriteByte(data[pos])
+				elPos = pos + 1
+				for k := 0; k < width; k++ {
+					color.WriteByte(data[elPos])
+					alpha.WriteByte(data[elPos+1])
+					elPos += 2
+				}
+			}
+		} else {
+			// RGB image
+			width := int(w)
+			height := int(h)
+			length := 4 * width
+			var pos, elPos int
+			for i := 0; i < height; i++ {
+				pos = (1 + length) * i
+				color.WriteByte(data[pos])
+				alpha.WriteByte(data[pos])
+				elPos = pos + 1
+				for k := 0; k < width; k++ {
+					color.Write(data[elPos : elPos+3])
+					alpha.WriteByte(data[elPos+3])
+					elPos += 4
+				}
+			}
+		}
+		data = sliceCompress(color.Bytes())
+		info.smask = sliceCompress(alpha.Bytes())
+		if f.pdfVersion < "1.4" {
+			f.pdfVersion = "1.4"
+		}
+	}
+	info.data = data
+	return
+}