src/pdf/SkPDFBitmap.cpp - skia - Git at Google

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "SkPDFBitmap.h"

 #include "SkColorData.h"
 #include "SkData.h"
 #include "SkDeflate.h"
 #include "SkExecutor.h"
 #include "SkImage.h"
 #include "SkImageInfoPriv.h"
 #include "SkJpegInfo.h"
 #include "SkPDFDocumentPriv.h"
 #include "SkPDFTypes.h"
 #include "SkPDFUtils.h"
 #include "SkStream.h"
 #include "SkTo.h"

 ////////////////////////////////////////////////////////////////////////////////

 // write a single byte to a stream n times.
 static void fill_stream(SkWStream* out, char value, size_t n) {
     char buffer[4096];
     memset(buffer, value, sizeof(buffer));
     for (size_t i = 0; i < n / sizeof(buffer); ++i) {
         out->write(buffer, sizeof(buffer));
     }
     out->write(buffer, n % sizeof(buffer));
 }

 /* It is necessary to average the color component of transparent
    pixels with their surrounding neighbors since the PDF renderer may
    separately re-sample the alpha and color channels when the image is
    not displayed at its native resolution. Since an alpha of zero
    gives no information about the color component, the pathological
    case is a white image with sharp transparency bounds - the color
    channel goes to black, and the should-be-transparent pixels are
    rendered as grey because of the separate soft mask and color
    resizing. e.g.: gm/bitmappremul.cpp */
 static SkColor get_neighbor_avg_color(const SkPixmap& bm, int xOrig, int yOrig) {
     SkASSERT(kBGRA_8888_SkColorType == bm.colorType());
     unsigned r = 0, g = 0, b = 0, n = 0;
     // Clamp the range to the edge of the bitmap.
     int ymin = SkTMax(0, yOrig - 1);
     int ymax = SkTMin(yOrig + 1, bm.height() - 1);
     int xmin = SkTMax(0, xOrig - 1);
     int xmax = SkTMin(xOrig + 1, bm.width() - 1);
     for (int y = ymin; y <= ymax; ++y) {
         const SkColor* scanline = bm.addr32(0, y);
         for (int x = xmin; x <= xmax; ++x) {
             SkColor color = scanline[x];
             if (color != SK_ColorTRANSPARENT) {
                 r += SkColorGetR(color);
                 g += SkColorGetG(color);
                 b += SkColorGetB(color);
                 n++;
             }
         }
     }
     return n > 0 ? SkColorSetRGB(SkToU8(r / n), SkToU8(g / n), SkToU8(b / n))
                  : SK_ColorTRANSPARENT;
 }

 template <typename T>
 static void emit_image_stream(SkPDFDocument* doc,
                               SkPDFIndirectReference ref,
                               T writeStream,
                               SkISize size,
                               const char* colorSpace,
                               SkPDFIndirectReference sMask,
                               int length,
                               bool isJpeg) {
     SkPDFDict pdfDict("XObject");
     pdfDict.insertName("Subtype", "Image");
     pdfDict.insertInt("Width", size.width());
     pdfDict.insertInt("Height", size.height());
     pdfDict.insertName("ColorSpace", colorSpace);
     if (sMask) {
         pdfDict.insertRef("SMask", sMask);
     }
     pdfDict.insertInt("BitsPerComponent", 8);
     #ifdef SK_PDF_BASE85_BINARY
     auto filters = SkPDFMakeArray();
     filters->appendName("ASCII85Decode");
     filters->appendName(isJpeg ? "DCTDecode" : "FlateDecode");
     pdfDict.insertObject("Filter", std::move(filters));
     #else
     pdfDict.insertName("Filter", isJpeg ? "DCTDecode" : "FlateDecode");
     #endif
     if (isJpeg) {
         pdfDict.insertInt("ColorTransform", 0);
     }
     pdfDict.insertInt("Length", length);
     doc->emitStream(pdfDict, std::move(writeStream), ref);
 }

 static void do_deflated_alpha(const SkPixmap& pm, SkPDFDocument* doc, SkPDFIndirectReference ref) {
     SkDynamicMemoryWStream buffer;
     SkDeflateWStream deflateWStream(&buffer);
     if (kAlpha_8_SkColorType == pm.colorType()) {
         SkASSERT(pm.rowBytes() == (size_t)pm.width());
         buffer.write(pm.addr8(), pm.width() * pm.height());
     } else {
         SkASSERT(pm.alphaType() == kUnpremul_SkAlphaType);
         SkASSERT(pm.colorType() == kBGRA_8888_SkColorType);
         SkASSERT(pm.rowBytes() == (size_t)pm.width() * 4);
         const uint32_t* ptr = pm.addr32();
         const uint32_t* stop = ptr + pm.height() * pm.width();

         uint8_t byteBuffer[4092];
         uint8_t* bufferStop = byteBuffer + SK_ARRAY_COUNT(byteBuffer);
         uint8_t* dst = byteBuffer;
         while (ptr != stop) {
             *dst++ = 0xFF & ((*ptr++) >> SK_BGRA_A32_SHIFT);
             if (dst == bufferStop) {
                 deflateWStream.write(byteBuffer, sizeof(byteBuffer));
                 dst = byteBuffer;
             }
         }
         deflateWStream.write(byteBuffer, dst - byteBuffer);
     }
     deflateWStream.finalize();

     #ifdef SK_PDF_BASE85_BINARY
     SkPDFUtils::Base85Encode(buffer.detachAsStream(), &buffer);
     #endif
     int length = SkToInt(buffer.bytesWritten());
     emit_image_stream(doc, ref, [&buffer](SkWStream* stream) { buffer.writeToAndReset(stream); },
                       pm.info().dimensions(), "DeviceGray", SkPDFIndirectReference(),
                       length, false);
 }

 static void do_deflated_image(const SkPixmap& pm,
                               SkPDFDocument* doc,
                               bool isOpaque,
                               SkPDFIndirectReference ref) {
     SkPDFIndirectReference sMask;
     if (!isOpaque) {
         sMask = doc->reserveRef();
     }
     SkDynamicMemoryWStream buffer;
     SkDeflateWStream deflateWStream(&buffer);
     const char* colorSpace = "DeviceGray";
     switch (pm.colorType()) {
         case kAlpha_8_SkColorType:
             fill_stream(&deflateWStream, '\x00', pm.width() * pm.height());
             break;
         case kGray_8_SkColorType:
             SkASSERT(sMask.fValue = -1);
             SkASSERT(pm.rowBytes() == (size_t)pm.width());
             deflateWStream.write(pm.addr8(), pm.width() * pm.height());
             break;
         default:
             colorSpace = "DeviceRGB";
             SkASSERT(pm.alphaType() == kUnpremul_SkAlphaType);
             SkASSERT(pm.colorType() == kBGRA_8888_SkColorType);
             SkASSERT(pm.rowBytes() == (size_t)pm.width() * 4);
             uint8_t byteBuffer[3072];
             static_assert(SK_ARRAY_COUNT(byteBuffer) % 3 == 0, "");
             uint8_t* bufferStop = byteBuffer + SK_ARRAY_COUNT(byteBuffer);
             uint8_t* dst = byteBuffer;
             for (int y = 0; y < pm.height(); ++y) {
                 const SkColor* src = pm.addr32(0, y);
                 for (int x = 0; x < pm.width(); ++x) {
                     SkColor color = *src++;
                     if (SkColorGetA(color) == SK_AlphaTRANSPARENT) {
                         color = get_neighbor_avg_color(pm, x, y);
                     }
                     *dst++ = SkColorGetR(color);
                     *dst++ = SkColorGetG(color);
                     *dst++ = SkColorGetB(color);
                     if (dst == bufferStop) {
                         deflateWStream.write(byteBuffer, sizeof(byteBuffer));
                         dst = byteBuffer;
                     }
                 }
             }
             deflateWStream.write(byteBuffer, dst - byteBuffer);
     }
     deflateWStream.finalize();
     #ifdef SK_PDF_BASE85_BINARY
     SkPDFUtils::Base85Encode(buffer.detachAsStream(), &buffer);
     #endif
     int length = SkToInt(buffer.bytesWritten());
     emit_image_stream(doc, ref, [&buffer](SkWStream* stream) { buffer.writeToAndReset(stream); },
                       pm.info().dimensions(), colorSpace, sMask, length, false);
     if (!isOpaque) {
         do_deflated_alpha(pm, doc, sMask);
     }
 }

 static bool do_jpeg(sk_sp<SkData> data, SkPDFDocument* doc, SkISize size,
                     SkPDFIndirectReference ref) {
     SkISize jpegSize;
     SkEncodedInfo::Color jpegColorType;
     SkEncodedOrigin exifOrientation;
     if (!SkGetJpegInfo(data->data(), data->size(), &jpegSize,
                        &jpegColorType, &exifOrientation)) {
         return false;
     }
     bool yuv = jpegColorType == SkEncodedInfo::kYUV_Color;
     bool goodColorType = yuv || jpegColorType == SkEncodedInfo::kGray_Color;
     if (jpegSize != size  // Sanity check.
             || !goodColorType
             || kTopLeft_SkEncodedOrigin != exifOrientation) {
         return false;
     }
     #ifdef SK_PDF_BASE85_BINARY
     SkDynamicMemoryWStream buffer;
     SkPDFUtils::Base85Encode(SkMemoryStream::MakeDirect(data->data(), data->size()), &buffer);
     data = buffer.detachAsData();
     #endif

     emit_image_stream(doc, ref,
                       [&data](SkWStream* dst) { dst->write(data->data(), data->size()); },
                       jpegSize, yuv ? "DeviceRGB" : "DeviceGray",
                       SkPDFIndirectReference(), SkToInt(data->size()), true);
     return true;
 }

 static SkBitmap to_pixels(const SkImage* image) {
     SkBitmap bm;
     int w = image->width(),
         h = image->height();
     switch (image->colorType()) {
         case kAlpha_8_SkColorType:
             bm.allocPixels(SkImageInfo::MakeA8(w, h));
             break;
         case kGray_8_SkColorType:
             bm.allocPixels(SkImageInfo::Make(w, h, kGray_8_SkColorType, kOpaque_SkAlphaType));
             break;
         default: {
             // TODO: makeColorSpace(sRGB) or actually tag the images
             SkAlphaType at = bm.isOpaque() ? kOpaque_SkAlphaType : kUnpremul_SkAlphaType;
             bm.allocPixels(SkImageInfo::Make(w, h, kBGRA_8888_SkColorType, at));
         }
     }
     if (!image->readPixels(bm.pixmap(), 0, 0)) {
         bm.eraseColor(SkColorSetARGB(0xFF, 0, 0, 0));
     }
     return bm;
 }

 void serialize_image(const SkImage* img,
                      int encodingQuality,
                      SkPDFDocument* doc,
                      SkPDFIndirectReference ref) {
     SkASSERT(img);
     SkASSERT(doc);
     SkASSERT(encodingQuality >= 0);
     SkISize dimensions = img->dimensions();
     sk_sp<SkData> data = img->refEncodedData();
     if (data && do_jpeg(std::move(data), doc, dimensions, ref)) {
         return;
     }
     SkBitmap bm = to_pixels(img);
     SkPixmap pm = bm.pixmap();
     bool isOpaque = pm.isOpaque() || pm.computeIsOpaque();
     if (encodingQuality <= 100 && isOpaque) {
         sk_sp<SkData> data = img->encodeToData(SkEncodedImageFormat::kJPEG, encodingQuality);
         if (data && do_jpeg(std::move(data), doc, dimensions, ref)) {
             return;
         }
     }
     do_deflated_image(pm, doc, isOpaque, ref);
 }

 SkPDFIndirectReference SkPDFSerializeImage(const SkImage* img,
                                            SkPDFDocument* doc,
                                            int encodingQuality) {
     SkASSERT(img);
     SkASSERT(doc);
     SkPDFIndirectReference ref = doc->reserveRef();
     if (SkExecutor* executor = doc->executor()) {
         SkRef(img);
         doc->incrementJobCount();
         executor->add([img, encodingQuality, doc, ref]() {
             serialize_image(img, encodingQuality, doc, ref);
             SkSafeUnref(img);
             doc->signalJobComplete();
         });
         return ref;
     }
     serialize_image(img, encodingQuality, doc, ref);
     return ref;
 }
	/*
	* Copyright 2015 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "SkPDFBitmap.h"

	#include "SkColorData.h"
	#include "SkData.h"
	#include "SkDeflate.h"
	#include "SkExecutor.h"
	#include "SkImage.h"
	#include "SkImageInfoPriv.h"
	#include "SkJpegInfo.h"
	#include "SkPDFDocumentPriv.h"
	#include "SkPDFTypes.h"
	#include "SkPDFUtils.h"
	#include "SkStream.h"
	#include "SkTo.h"

	////////////////////////////////////////////////////////////////////////////////

	// write a single byte to a stream n times.
	static void fill_stream(SkWStream* out, char value, size_t n) {
	char buffer[4096];
	memset(buffer, value, sizeof(buffer));
	for (size_t i = 0; i < n / sizeof(buffer); ++i) {
	out->write(buffer, sizeof(buffer));
	}
	out->write(buffer, n % sizeof(buffer));
	}

	/* It is necessary to average the color component of transparent
	pixels with their surrounding neighbors since the PDF renderer may
	separately re-sample the alpha and color channels when the image is
	not displayed at its native resolution. Since an alpha of zero
	gives no information about the color component, the pathological
	case is a white image with sharp transparency bounds - the color
	channel goes to black, and the should-be-transparent pixels are
	rendered as grey because of the separate soft mask and color
	resizing. e.g.: gm/bitmappremul.cpp */
	static SkColor get_neighbor_avg_color(const SkPixmap& bm, int xOrig, int yOrig) {
	SkASSERT(kBGRA_8888_SkColorType == bm.colorType());
	unsigned r = 0, g = 0, b = 0, n = 0;
	// Clamp the range to the edge of the bitmap.
	int ymin = SkTMax(0, yOrig - 1);
	int ymax = SkTMin(yOrig + 1, bm.height() - 1);
	int xmin = SkTMax(0, xOrig - 1);
	int xmax = SkTMin(xOrig + 1, bm.width() - 1);
	for (int y = ymin; y <= ymax; ++y) {
	const SkColor* scanline = bm.addr32(0, y);
	for (int x = xmin; x <= xmax; ++x) {
	SkColor color = scanline[x];
	if (color != SK_ColorTRANSPARENT) {
	r += SkColorGetR(color);
	g += SkColorGetG(color);
	b += SkColorGetB(color);
	n++;
	}
	}
	}
	return n > 0 ? SkColorSetRGB(SkToU8(r / n), SkToU8(g / n), SkToU8(b / n))
	: SK_ColorTRANSPARENT;
	}

	template <typename T>
	static void emit_image_stream(SkPDFDocument* doc,
	SkPDFIndirectReference ref,
	T writeStream,
	SkISize size,
	const char* colorSpace,
	SkPDFIndirectReference sMask,
	int length,
	bool isJpeg) {
	SkPDFDict pdfDict("XObject");
	pdfDict.insertName("Subtype", "Image");
	pdfDict.insertInt("Width", size.width());
	pdfDict.insertInt("Height", size.height());
	pdfDict.insertName("ColorSpace", colorSpace);
	if (sMask) {
	pdfDict.insertRef("SMask", sMask);
	}
	pdfDict.insertInt("BitsPerComponent", 8);
	#ifdef SK_PDF_BASE85_BINARY
	auto filters = SkPDFMakeArray();
	filters->appendName("ASCII85Decode");
	filters->appendName(isJpeg ? "DCTDecode" : "FlateDecode");
	pdfDict.insertObject("Filter", std::move(filters));
	#else
	pdfDict.insertName("Filter", isJpeg ? "DCTDecode" : "FlateDecode");
	#endif
	if (isJpeg) {
	pdfDict.insertInt("ColorTransform", 0);
	}
	pdfDict.insertInt("Length", length);
	doc->emitStream(pdfDict, std::move(writeStream), ref);
	}

	static void do_deflated_alpha(const SkPixmap& pm, SkPDFDocument* doc, SkPDFIndirectReference ref) {
	SkDynamicMemoryWStream buffer;
	SkDeflateWStream deflateWStream(&buffer);
	if (kAlpha_8_SkColorType == pm.colorType()) {
	SkASSERT(pm.rowBytes() == (size_t)pm.width());
	buffer.write(pm.addr8(), pm.width() * pm.height());
	} else {
	SkASSERT(pm.alphaType() == kUnpremul_SkAlphaType);
	SkASSERT(pm.colorType() == kBGRA_8888_SkColorType);
	SkASSERT(pm.rowBytes() == (size_t)pm.width() * 4);
	const uint32_t* ptr = pm.addr32();
	const uint32_t* stop = ptr + pm.height() * pm.width();

	uint8_t byteBuffer[4092];
	uint8_t* bufferStop = byteBuffer + SK_ARRAY_COUNT(byteBuffer);
	uint8_t* dst = byteBuffer;
	while (ptr != stop) {
	dst++ = 0xFF & ((ptr++) >> SK_BGRA_A32_SHIFT);
	if (dst == bufferStop) {
	deflateWStream.write(byteBuffer, sizeof(byteBuffer));
	dst = byteBuffer;
	}
	}
	deflateWStream.write(byteBuffer, dst - byteBuffer);
	}
	deflateWStream.finalize();

	#ifdef SK_PDF_BASE85_BINARY
	SkPDFUtils::Base85Encode(buffer.detachAsStream(), &buffer);
	#endif
	int length = SkToInt(buffer.bytesWritten());
	emit_image_stream(doc, ref, [&buffer](SkWStream* stream) { buffer.writeToAndReset(stream); },
	pm.info().dimensions(), "DeviceGray", SkPDFIndirectReference(),
	length, false);
	}

	static void do_deflated_image(const SkPixmap& pm,
	SkPDFDocument* doc,
	bool isOpaque,
	SkPDFIndirectReference ref) {
	SkPDFIndirectReference sMask;
	if (!isOpaque) {
	sMask = doc->reserveRef();
	}
	SkDynamicMemoryWStream buffer;
	SkDeflateWStream deflateWStream(&buffer);
	const char* colorSpace = "DeviceGray";
	switch (pm.colorType()) {
	case kAlpha_8_SkColorType:
	fill_stream(&deflateWStream, '\x00', pm.width() * pm.height());
	break;
	case kGray_8_SkColorType:
	SkASSERT(sMask.fValue = -1);
	SkASSERT(pm.rowBytes() == (size_t)pm.width());
	deflateWStream.write(pm.addr8(), pm.width() * pm.height());
	break;
	default:
	colorSpace = "DeviceRGB";
	SkASSERT(pm.alphaType() == kUnpremul_SkAlphaType);
	SkASSERT(pm.colorType() == kBGRA_8888_SkColorType);
	SkASSERT(pm.rowBytes() == (size_t)pm.width() * 4);
	uint8_t byteBuffer[3072];
	static_assert(SK_ARRAY_COUNT(byteBuffer) % 3 == 0, "");
	uint8_t* bufferStop = byteBuffer + SK_ARRAY_COUNT(byteBuffer);
	uint8_t* dst = byteBuffer;
	for (int y = 0; y < pm.height(); ++y) {
	const SkColor* src = pm.addr32(0, y);
	for (int x = 0; x < pm.width(); ++x) {
	SkColor color = *src++;
	if (SkColorGetA(color) == SK_AlphaTRANSPARENT) {
	color = get_neighbor_avg_color(pm, x, y);
	}
	*dst++ = SkColorGetR(color);
	*dst++ = SkColorGetG(color);
	*dst++ = SkColorGetB(color);
	if (dst == bufferStop) {
	deflateWStream.write(byteBuffer, sizeof(byteBuffer));
	dst = byteBuffer;
	}
	}
	}
	deflateWStream.write(byteBuffer, dst - byteBuffer);
	}
	deflateWStream.finalize();
	#ifdef SK_PDF_BASE85_BINARY
	SkPDFUtils::Base85Encode(buffer.detachAsStream(), &buffer);
	#endif
	int length = SkToInt(buffer.bytesWritten());
	emit_image_stream(doc, ref, [&buffer](SkWStream* stream) { buffer.writeToAndReset(stream); },
	pm.info().dimensions(), colorSpace, sMask, length, false);
	if (!isOpaque) {
	do_deflated_alpha(pm, doc, sMask);
	}
	}

	static bool do_jpeg(sk_sp<SkData> data, SkPDFDocument* doc, SkISize size,
	SkPDFIndirectReference ref) {
	SkISize jpegSize;
	SkEncodedInfo::Color jpegColorType;
	SkEncodedOrigin exifOrientation;
	if (!SkGetJpegInfo(data->data(), data->size(), &jpegSize,
	&jpegColorType, &exifOrientation)) {
	return false;
	}
	bool yuv = jpegColorType == SkEncodedInfo::kYUV_Color;
	bool goodColorType = yuv \|\| jpegColorType == SkEncodedInfo::kGray_Color;
	if (jpegSize != size // Sanity check.
	\|\| !goodColorType
	\|\| kTopLeft_SkEncodedOrigin != exifOrientation) {
	return false;
	}
	#ifdef SK_PDF_BASE85_BINARY
	SkDynamicMemoryWStream buffer;
	SkPDFUtils::Base85Encode(SkMemoryStream::MakeDirect(data->data(), data->size()), &buffer);
	data = buffer.detachAsData();
	#endif

	emit_image_stream(doc, ref,
	[&data](SkWStream* dst) { dst->write(data->data(), data->size()); },
	jpegSize, yuv ? "DeviceRGB" : "DeviceGray",
	SkPDFIndirectReference(), SkToInt(data->size()), true);
	return true;
	}

	static SkBitmap to_pixels(const SkImage* image) {
	SkBitmap bm;
	int w = image->width(),
	h = image->height();
	switch (image->colorType()) {
	case kAlpha_8_SkColorType:
	bm.allocPixels(SkImageInfo::MakeA8(w, h));
	break;
	case kGray_8_SkColorType:
	bm.allocPixels(SkImageInfo::Make(w, h, kGray_8_SkColorType, kOpaque_SkAlphaType));
	break;
	default: {
	// TODO: makeColorSpace(sRGB) or actually tag the images
	SkAlphaType at = bm.isOpaque() ? kOpaque_SkAlphaType : kUnpremul_SkAlphaType;
	bm.allocPixels(SkImageInfo::Make(w, h, kBGRA_8888_SkColorType, at));
	}
	}
	if (!image->readPixels(bm.pixmap(), 0, 0)) {
	bm.eraseColor(SkColorSetARGB(0xFF, 0, 0, 0));
	}
	return bm;
	}

	void serialize_image(const SkImage* img,
	int encodingQuality,
	SkPDFDocument* doc,
	SkPDFIndirectReference ref) {
	SkASSERT(img);
	SkASSERT(doc);
	SkASSERT(encodingQuality >= 0);
	SkISize dimensions = img->dimensions();
	sk_sp<SkData> data = img->refEncodedData();
	if (data && do_jpeg(std::move(data), doc, dimensions, ref)) {
	return;
	}
	SkBitmap bm = to_pixels(img);
	SkPixmap pm = bm.pixmap();
	bool isOpaque = pm.isOpaque() \|\| pm.computeIsOpaque();
	if (encodingQuality <= 100 && isOpaque) {
	sk_sp<SkData> data = img->encodeToData(SkEncodedImageFormat::kJPEG, encodingQuality);
	if (data && do_jpeg(std::move(data), doc, dimensions, ref)) {
	return;
	}
	}
	do_deflated_image(pm, doc, isOpaque, ref);
	}

	SkPDFIndirectReference SkPDFSerializeImage(const SkImage* img,
	SkPDFDocument* doc,
	int encodingQuality) {
	SkASSERT(img);
	SkASSERT(doc);
	SkPDFIndirectReference ref = doc->reserveRef();
	if (SkExecutor* executor = doc->executor()) {
	SkRef(img);
	doc->incrementJobCount();
	executor->add([img, encodingQuality, doc, ref]() {
	serialize_image(img, encodingQuality, doc, ref);
	SkSafeUnref(img);
	doc->signalJobComplete();
	});
	return ref;
	}
	serialize_image(img, encodingQuality, doc, ref);
	return ref;
	}