gecko-dev/modules/libimg/pngcom/png_png.cpp

141 lines
4.6 KiB
C++

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape 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/NPL/
*
* 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 mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
/* png_png.c - modified from example.c code */
#include "png.h"
#include "nsIImgDecoder.h" // include if_struct.h Needs to be first
#include "ipng.h"
#include "nsPNGDecoder.h"
#include "nsIImgDCallbk.h"
extern void png_set_dims(il_container *, png_structp);
void info_callback(png_structp png_ptr, png_infop info)
{
/* do any setup here, including setting any of the transformations
* mentioned in the Reading PNG files section. For now, you _must_
* call either png_start_read_image() or png_read_update_info()
* after all the transformations are set (even if you don't set
* any). You may start getting rows before png_process_data()
* returns, so this is your last chance to prepare for that.
*/
int number_passes;
double screen_gamma;
/*always decode to 24 bit*/
if(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->bit_depth <= 8)
png_set_expand(png_ptr);
if(png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth <= 8){
png_set_gray_to_rgb(png_ptr);
png_set_expand(png_ptr);
}
if(png_get_valid(png_ptr, info, PNG_INFO_tRNS))
png_set_expand(png_ptr);
/* implement scr gamma for mac & unix. (do preferences later.) */
#ifdef XP_MAC
screen_gamma = 1.7; /*Mac : 1.7 */
#else
screen_gamma = 2.2; /*good for PC.*/
#endif
/*
if (png_get_gAMA(png_ptr, info, (double *)&png_ptr->gamma))
png_set_gamma(png_ptr, screen_gamma, png_ptr->gamma);
else
png_set_gamma(png_ptr, screen_gamma, 0.45);
*/
if(png_ptr->interlaced == PNG_INTERLACE_ADAM7)
number_passes = png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info);
/* Set the ic values */
png_set_dims((il_container *)png_ptr->io_ptr, png_ptr);
}
void row_callback( png_structp png_ptr, png_bytep new_row,
png_uint_32 row_num, int pass )
{
/* this function is called for every row in the image. If the
* image is interlacing, and you turned on the interlace handler,
* this function will be called for every row in every pass.
* Some of these rows will not be changed from the previous pass.
* When the row is not changed, the new_row variable will be NULL.
* The rows and passes are called in order, so you don't really
* need the row_num and pass, but I'm supplying them because it
* may make your life easier.
*
* For the non-NULL rows of interlaced images, you must call
* png_progressive_combine_row() passing in the row and the
* old row. You can call this function for NULL rows (it will
* just return) and for non-interlaced images (it just does the
* memcpy for you) if it will make the code easier. Thus, you
* can just do this for all cases:
*/
il_container *ic = (il_container *)png_ptr->io_ptr;
if(new_row){
ic->imgdcb->ImgDCBHaveRow( 0, new_row, 0, png_ptr->width,
row_num, 1, ilErase /* ilOverlay */, png_ptr->pass );
/* il_flush_image_data(png_ptr->io_ptr); */
}
/* where old_row is what was displayed for previous rows. Note
* that the first pass (pass == 0 really) will completely cover
* the old row, so the rows do not have to be initialized. After
* the first pass (and only for interlaced images), you will have
* to pass the current row, and the function will combine the
* old row and the new row.
*/
}
void end_callback(png_structp png_ptr, png_infop info)
{
/* this function is called when the whole image has been read,
* including any chunks after the image (up to and including
* the IEND). You will usually have the same info chunk as you
* had in the header, although some data may have been added
* to the comments and time fields.
*
* Most people won't do much here, perhaps setting a flag that
* marks the image as finished.
*/
il_container *ic = (il_container *)png_ptr->io_ptr;
ic->imgdcb->ImgDCBFlushImage();
}