pjs/modules/libpr0n/encoders/png/nsPNGEncoder.cpp

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Исходник Обычный вид История

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is PNG Encoding code
*
* The Initial Developer of the Original Code is
* Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Brett Wilson <brettw@gmail.com>
* Stuart Parmenter <pavlov@pavlov.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsPNGEncoder.h"
#include "prmem.h"
#include "nsString.h"
#include "nsStreamUtils.h"
// Bug 308126 - AIX defines jmpbuf in sys/context.h which conflicts with the
// definition of jmpbuf in the png.h header file.
#ifdef jmpbuf
#undef jmpbuf
#endif
// Input streams that do not implement nsIAsyncInputStream should be threadsafe
// so that they may be used with nsIInputStreamPump and nsIInputStreamChannel,
// which read such a stream on a background thread.
NS_IMPL_THREADSAFE_ISUPPORTS2(nsPNGEncoder, imgIEncoder, nsIInputStream)
nsPNGEncoder::nsPNGEncoder() : mImageBuffer(nsnull), mImageBufferSize(0),
mImageBufferUsed(0), mImageBufferReadPoint(0)
{
}
nsPNGEncoder::~nsPNGEncoder()
{
if (mImageBuffer) {
PR_Free(mImageBuffer);
mImageBuffer = nsnull;
}
}
// nsPNGEncoder::InitFromData
//
// One output option is supported: "transparency=none" means that the
// output PNG will not have an alpha channel, even if the input does.
//
// Based partially on gfx/cairo/cairo/src/cairo-png.c
// See also modules/libimg/png/libpng.txt
NS_IMETHODIMP nsPNGEncoder::InitFromData(const PRUint8* aData,
PRUint32 aLength, // (unused, req'd by JS)
PRUint32 aWidth,
PRUint32 aHeight,
PRUint32 aStride,
PRUint32 aInputFormat,
const nsAString& aOutputOptions)
{
// validate input format
if (aInputFormat != INPUT_FORMAT_RGB &&
aInputFormat != INPUT_FORMAT_RGBA &&
aInputFormat != INPUT_FORMAT_HOSTARGB)
return NS_ERROR_INVALID_ARG;
// Stride is the padded width of each row, so it better be longer (I'm afraid
// people will not understand what stride means, so check it well)
if ((aInputFormat == INPUT_FORMAT_RGB &&
aStride < aWidth * 3) ||
((aInputFormat == INPUT_FORMAT_RGBA || aInputFormat == INPUT_FORMAT_HOSTARGB) &&
aStride < aWidth * 4)) {
NS_WARNING("Invalid stride for InitFromData");
return NS_ERROR_INVALID_ARG;
}
// can't initialize more than once
if (mImageBuffer != nsnull)
return NS_ERROR_ALREADY_INITIALIZED;
// options: we only have one option so this is easy
PRBool useTransparency = PR_TRUE;
if (aOutputOptions.Length() >= 17) {
if (StringBeginsWith(aOutputOptions, NS_LITERAL_STRING("transparency=none")))
useTransparency = PR_FALSE;
}
// initialize
png_struct* png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
png_voidp_NULL,
png_error_ptr_NULL,
png_error_ptr_NULL);
if (! png_ptr)
return NS_ERROR_OUT_OF_MEMORY;
png_info* info_ptr = png_create_info_struct(png_ptr);
if (! info_ptr)
{
png_destroy_write_struct(&png_ptr, nsnull);
return NS_ERROR_FAILURE;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return NS_ERROR_OUT_OF_MEMORY;
}
// Set up to read the data into our image buffer, start out with an 8K
// estimated size. Note: we don't have to worry about freeing this data
// in this function. It will be freed on object destruction.
mImageBufferSize = 8192;
mImageBuffer = (PRUint8*)PR_Malloc(mImageBufferSize);
if (!mImageBuffer) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return NS_ERROR_OUT_OF_MEMORY;
}
mImageBufferUsed = 0;
// set our callback for libpng to give us the data
png_set_write_fn(png_ptr, this, WriteCallback, NULL);
// include alpha?
int colorType;
if ((aInputFormat == INPUT_FORMAT_HOSTARGB ||
aInputFormat == INPUT_FORMAT_RGBA) && useTransparency)
colorType = PNG_COLOR_TYPE_RGB_ALPHA;
else
colorType = PNG_COLOR_TYPE_RGB;
png_set_IHDR(png_ptr, info_ptr, aWidth, aHeight, 8, colorType,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
PNG_FILTER_TYPE_DEFAULT);
png_write_info(png_ptr, info_ptr);
// write each row: if we add more input formats, we may want to
// generalize the conversions
if (aInputFormat == INPUT_FORMAT_HOSTARGB) {
// PNG requires RGBA with post-multiplied alpha, so we need to convert
PRUint8* row = new PRUint8[aWidth * 4];
for (PRUint32 y = 0; y < aHeight; y ++) {
ConvertHostARGBRow(&aData[y * aStride], row, aWidth, useTransparency);
png_write_row(png_ptr, row);
}
delete[] row;
} else if (aInputFormat == INPUT_FORMAT_RGBA && ! useTransparency) {
// RBGA, but we need to strip the alpha
PRUint8* row = new PRUint8[aWidth * 4];
for (PRUint32 y = 0; y < aHeight; y ++) {
StripAlpha(&aData[y * aStride], row, aWidth);
png_write_row(png_ptr, row);
}
delete[] row;
} else if (aInputFormat == INPUT_FORMAT_RGB ||
aInputFormat == INPUT_FORMAT_RGBA) {
// simple RBG(A), no conversion needed
for (PRUint32 y = 0; y < aHeight; y ++) {
png_write_row(png_ptr, (PRUint8*)&aData[y * aStride]);
}
} else {
NS_NOTREACHED("Bad format type");
}
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
// if output callback can't get enough memory, it will free our buffer
if (!mImageBuffer)
return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
/* void close (); */
NS_IMETHODIMP nsPNGEncoder::Close()
{
if (mImageBuffer != nsnull) {
PR_Free(mImageBuffer);
mImageBuffer = nsnull;
mImageBufferSize = 0;
mImageBufferUsed = 0;
mImageBufferReadPoint = 0;
}
return NS_OK;
}
/* unsigned long available (); */
NS_IMETHODIMP nsPNGEncoder::Available(PRUint32 *_retval)
{
if (!mImageBuffer)
return NS_BASE_STREAM_CLOSED;
*_retval = mImageBufferUsed - mImageBufferReadPoint;
return NS_OK;
}
/* [noscript] unsigned long read (in charPtr aBuf, in unsigned long aCount); */
NS_IMETHODIMP nsPNGEncoder::Read(char * aBuf, PRUint32 aCount,
PRUint32 *_retval)
{
return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, _retval);
}
/* [noscript] unsigned long readSegments (in nsWriteSegmentFun aWriter, in voidPtr aClosure, in unsigned long aCount); */
NS_IMETHODIMP nsPNGEncoder::ReadSegments(nsWriteSegmentFun aWriter,
void *aClosure, PRUint32 aCount,
PRUint32 *_retval)
{
PRUint32 maxCount = mImageBufferUsed - mImageBufferReadPoint;
if (maxCount == 0) {
*_retval = 0;
return NS_OK;
}
if (aCount > maxCount)
aCount = maxCount;
nsresult rv = aWriter(this, aClosure,
NS_REINTERPRET_CAST(const char*, mImageBuffer),
0, aCount, _retval);
if (NS_SUCCEEDED(rv)) {
NS_ASSERTION(*_retval <= aCount, "bad write count");
mImageBufferReadPoint += *_retval;
}
// errors returned from the writer end here!
return NS_OK;
}
/* boolean isNonBlocking (); */
NS_IMETHODIMP nsPNGEncoder::IsNonBlocking(PRBool *_retval)
{
*_retval = PR_FALSE; // We don't implement nsIAsyncInputStream
return NS_OK;
}
// nsPNGEncoder::ConvertHostARGBRow
//
// Our colors are stored with premultiplied alphas, but PNGs use
// post-multiplied alpha. This swaps to PNG-style alpha.
//
// Copied from gfx/cairo/cairo/src/cairo-png.c
void
nsPNGEncoder::ConvertHostARGBRow(const PRUint8* aSrc, PRUint8* aDest,
PRUint32 aPixelWidth, PRBool aUseTransparency)
{
PRUint32 pixelStride = aUseTransparency ? 4 : 3;
for (PRUint32 x = 0; x < aPixelWidth; x ++) {
const PRUint32& pixelIn = ((const PRUint32*)(aSrc))[x];
PRUint8 *pixelOut = &aDest[x * pixelStride];
PRUint8 alpha = (pixelIn & 0xff000000) >> 24;
if (alpha == 0) {
pixelOut[0] = pixelOut[1] = pixelOut[2] = pixelOut[3] = 0;
} else {
pixelOut[0] = (((pixelIn & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
pixelOut[1] = (((pixelIn & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
pixelOut[2] = (((pixelIn & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
if (aUseTransparency)
pixelOut[3] = alpha;
}
}
}
// nsPNGEncoder::StripAlpha
//
// Input is RGBA, output is RGB
void
nsPNGEncoder::StripAlpha(const PRUint8* aSrc, PRUint8* aDest,
PRUint32 aPixelWidth)
{
for (PRUint32 x = 0; x < aPixelWidth; x ++) {
const PRUint8* pixelIn = &aSrc[x * 4];
PRUint8* pixelOut = &aDest[x * 3];
pixelOut[0] = pixelIn[0];
pixelOut[1] = pixelIn[1];
pixelOut[2] = pixelIn[2];
}
}
// nsPNGEncoder::WriteCallback
void // static
nsPNGEncoder::WriteCallback(png_structp png, png_bytep data, png_size_t size)
{
nsPNGEncoder* that = NS_STATIC_CAST(nsPNGEncoder*, png_get_io_ptr(png));
if (! that->mImageBuffer)
return;
if (that->mImageBufferUsed + size > that->mImageBufferSize) {
// expand buffer, just double each time
that->mImageBufferSize *= 2;
PRUint8* newBuf = (PRUint8*)PR_Realloc(that->mImageBuffer,
that->mImageBufferSize);
if (! newBuf) {
// can't resize, just zero (this will keep us from writing more)
PR_Free(that->mImageBuffer);
that->mImageBufferSize = 0;
that->mImageBufferUsed = 0;
return;
}
that->mImageBuffer = newBuf;
}
memcpy(&that->mImageBuffer[that->mImageBufferUsed], data, size);
that->mImageBufferUsed += size;
}