mirror of https://github.com/fltk/fltk
240 lines
6.7 KiB
C++
240 lines
6.7 KiB
C++
//
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// "$Id$"
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//
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// Fl_PNG_Image routines.
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//
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// Copyright 1997-2012 by Easy Software Products.
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// Image support by Matthias Melcher, Copyright 2000-2009.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// http://www.fltk.org/COPYING.php
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//
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// Please report all bugs and problems on the following page:
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//
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// http://www.fltk.org/str.php
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//
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// Contents:
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//
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// Fl_PNG_Image::Fl_PNG_Image() - Load a PNG image file.
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//
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//
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// Include necessary header files...
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//
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#include <FL/Fl.H>
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#include <FL/Fl_PNG_Image.H>
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#include <FL/Fl_Shared_Image.H>
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <FL/fl_utf8.h>
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#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
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extern "C"
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{
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# include <zlib.h>
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# ifdef HAVE_PNG_H
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# include <png.h>
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# else
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# include <libpng/png.h>
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# endif // HAVE_PNG_H
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}
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typedef struct {
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png_structp pp;
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const unsigned char *current;
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const unsigned char *last;
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} fl_png_memory;
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extern "C" {
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static void png_read_data_from_mem( png_structp png_ptr, //pointer to our data
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png_bytep data, // where to copy the image data for libpng computing
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png_size_t length) // length of data to copy
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{
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fl_png_memory *png_mem_data = (fl_png_memory*)png_get_io_ptr(png_ptr); // get the pointer to our struct
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if (png_mem_data->current + length > png_mem_data->last) {
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png_error(png_mem_data->pp, "Invalid attempt to read row data");
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return;
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}
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/* copy data from image buffer */
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memcpy (data, png_mem_data->current, length);
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/* advance in the memory data */
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png_mem_data->current += length;
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}
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} // extern "C"
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#endif // HAVE_LIBPNG && HAVE_LIBZ
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/**
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The constructor loads the named PNG image from the given png filename.
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The destructor frees all memory and server resources that are used by
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the image.
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Use Fl_Image::fail() to check if Fl_PNG_Image failed to load. fail() returns
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ERR_FILE_ACCESS if the file could not be opened or read, ERR_FORMAT if the
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PNG format could not be decoded, and ERR_NO_IMAGE if the image could not
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be loaded for another reason.
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\param[in] filename Name of PNG file to read
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*/
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Fl_PNG_Image::Fl_PNG_Image (const char *filename): Fl_RGB_Image(0,0,0)
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{
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load_png_(filename, NULL, 0);
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}
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/**
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\brief Constructor that reads a PNG image from memory.
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Construct an image from a block of memory inside the application. Fluid offers
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"binary Data" chunks as a great way to add image data into the C++ source code.
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name_png can be NULL. If a name is given, the image is added to the list of
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shared images (see: Fl_Shared_Image) and will be available by that name.
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\param name_png A name given to this image or NULL
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\param buffer Pointer to the start of the PNG image in memory
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\param maxsize Size in bytes of the memory buffer containing the PNG image
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*/
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Fl_PNG_Image::Fl_PNG_Image (
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const char *name_png, const unsigned char *buffer, int maxsize): Fl_RGB_Image(0,0,0)
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{
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load_png_(name_png, buffer, maxsize);
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}
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void Fl_PNG_Image::load_png_(const char *name_png, const unsigned char *buffer_png, int maxsize)
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{
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#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
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int i; // Looping var
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FILE *fp = NULL; // File pointer
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int channels; // Number of color channels
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png_structp pp; // PNG read pointer
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png_infop info; // PNG info pointers
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png_bytep *rows;// PNG row pointers
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fl_png_memory png_mem_data;
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int from_memory = (buffer_png != NULL); // true if reading image from memory
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if (!from_memory) {
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if ((fp = fl_fopen(name_png, "rb")) == NULL) {
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ld(ERR_FILE_ACCESS);
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return;
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}
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}
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const char *display_name = (name_png ? name_png : "In-memory PNG data");
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// Setup the PNG data structures...
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pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
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if (pp) info = png_create_info_struct(pp);
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if (!pp || !info) {
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if (pp) png_destroy_read_struct(&pp, NULL, NULL);
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if (!from_memory) fclose(fp);
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Fl::warning("Cannot allocate memory to read PNG file or data \"%s\".\n", display_name);
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w(0); h(0); d(0); ld(ERR_FORMAT);
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return;
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}
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if (setjmp(png_jmpbuf(pp)))
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{
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png_destroy_read_struct(&pp, &info, NULL);
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if (!from_memory) fclose(fp);
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Fl::warning("PNG file or data \"%s\" is too large or contains errors!\n", display_name);
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w(0); h(0); d(0); ld(ERR_FORMAT);
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return;
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}
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if (from_memory) {
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png_mem_data.current = buffer_png;
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png_mem_data.last = buffer_png + maxsize;
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png_mem_data.pp = pp;
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// Initialize the function pointer to the PNG read "engine"...
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png_set_read_fn (pp, (png_voidp) &png_mem_data, png_read_data_from_mem);
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} else {
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png_init_io(pp, fp); // Initialize the PNG file read "engine"...
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}
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// Get the image dimensions and convert to grayscale or RGB...
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png_read_info(pp, info);
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if (png_get_color_type(pp, info) == PNG_COLOR_TYPE_PALETTE)
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png_set_expand(pp);
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if (png_get_color_type(pp, info) & PNG_COLOR_MASK_COLOR)
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channels = 3;
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else
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channels = 1;
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int num_trans = 0;
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png_get_tRNS(pp, info, 0, &num_trans, 0);
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if ((png_get_color_type(pp, info) & PNG_COLOR_MASK_ALPHA) || (num_trans != 0))
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channels ++;
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w((int)(png_get_image_width(pp, info)));
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h((int)(png_get_image_height(pp, info)));
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d(channels);
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if (png_get_bit_depth(pp, info) < 8)
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{
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png_set_packing(pp);
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png_set_expand(pp);
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}
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else if (png_get_bit_depth(pp, info) == 16)
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png_set_strip_16(pp);
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# if defined(HAVE_PNG_GET_VALID) && defined(HAVE_PNG_SET_TRNS_TO_ALPHA)
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// Handle transparency...
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if (png_get_valid(pp, info, PNG_INFO_tRNS))
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png_set_tRNS_to_alpha(pp);
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# endif // HAVE_PNG_GET_VALID && HAVE_PNG_SET_TRNS_TO_ALPHA
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if (((size_t)w()) * h() * d() > max_size() ) longjmp(png_jmpbuf(pp), 1);
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array = new uchar[w() * h() * d()];
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alloc_array = 1;
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// Allocate pointers...
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rows = new png_bytep[h()];
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for (i = 0; i < h(); i ++)
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rows[i] = (png_bytep)(array + i * w() * d());
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// Read the image, handling interlacing as needed...
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for (i = png_set_interlace_handling(pp); i > 0; i --)
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png_read_rows(pp, rows, NULL, h());
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#ifdef WIN32
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// Some Windows graphics drivers don't honor transparency when RGB == white
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if (channels == 4) {
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// Convert RGB to 0 when alpha == 0...
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uchar *ptr = (uchar *)array;
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for (i = w() * h(); i > 0; i --, ptr += 4)
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if (!ptr[3]) ptr[0] = ptr[1] = ptr[2] = 0;
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}
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#endif // WIN32
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// Free memory and return...
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delete[] rows;
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png_read_end(pp, info);
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png_destroy_read_struct(&pp, &info, NULL);
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if (from_memory) {
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if (w() && h() && name_png) {
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Fl_Shared_Image *si = new Fl_Shared_Image(name_png, this);
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si->add();
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}
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} else {
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fclose(fp);
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}
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#endif // HAVE_LIBPNG && HAVE_LIBZ
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}
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//
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// End of "$Id$".
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//
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