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Diffstat (limited to 'src/png.c')
| -rw-r--r-- | src/png.c | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/src/png.c b/src/png.c new file mode 100644 index 00000000..43ef5519 --- /dev/null +++ b/src/png.c @@ -0,0 +1,472 @@ +/* + * The png decoder for Dillo. It is responsible for decoding PNG data + * and transferring it to the dicache. + * + * Geoff Lane nov 1999 zzassgl@twirl.mcc.ac.uk + * Luca Rota, Jorge Arellano Cid, Eric Gaudet 2000 + * + * "PNG: The Definitive Guide" by Greg Roelofs, O'Reilly + * ISBN 1-56592-542-4 + */ + +#include <config.h> +#ifdef ENABLE_PNG + +#include <stdio.h> +#include <string.h> +#include <stdlib.h> /* For abort() */ + +#include <zlib.h> + +#ifdef HAVE_LIBPNG_PNG_H +#include <libpng/png.h> +#else +#include <png.h> +#endif + +#include "msg.h" +#include "image.hh" +#include "web.hh" +#include "cache.h" +#include "dicache.h" +#include "prefs.h" + +#define DEBUG_LEVEL 6 +#include "debug.h" + +enum prog_state { + IS_finished, IS_init, IS_nextdata +}; + +static char *prog_state_name[] = +{ + "IS_finished", "IS_init", "IS_nextdata" +}; + +/* + * This holds the data that must be saved between calls to this module. + * Each time it is called it is supplied with a vector of data bytes + * obtained from the web server. The module can process any amount of the + * supplied data. The next time the module is called, the vector may be + * extended with additional data bytes to be processed. The module must + * keep track of the current start and cursor position of the input data + * vector. As complete output rasters are determined they are sent out of + * the module for additional processing. + * + * NOTE: There is no external control of the splitting of the input data + * vector (only this module understands PNG format data.) This means that + * the complete state of a PNG image being processed must be held in the + * structure below so that processing can be suspended or resumed at any + * point within an input image. + * + * In the case of the libpng library, it maintains it's own state in + * png_ptr and into_ptr so the FSM is very simple - much simpler than the + * ones for XBM and PNM are. + */ + +typedef +struct _DilloPng { + DilloImage *Image; /* Image meta data */ + DilloUrl *url; /* Primary Key for the dicache */ + int version; /* Secondary Key for the dicache */ + + double display_exponent; /* gamma correction */ + ulong_t width; /* png image width */ + ulong_t height; /* png image height */ + png_structp png_ptr; /* libpng private data */ + png_infop info_ptr; /* libpng private info */ + uchar_t *image_data; /* decoded image data */ + uchar_t **row_pointers; /* pntr to row starts */ + jmp_buf jmpbuf; /* png error processing */ + int error; /* error flag */ + int rowbytes; /* No. bytes in image row */ + short passes; + short channels; /* No. image channels */ + +/* + * 0 last byte + * +-------+-+-----------------------------------+-+ + * | | | -- data to be processed -- | | + * +-------+-+-----------------------------------+-+ + * ^ ^ ^ + * ipbuf ipbufstart ipbufsize + */ + + uchar_t *ipbuf; /* image data in buffer */ + int ipbufstart; /* first valid image byte */ + int ipbufsize; /* size of valid data in */ + + enum prog_state state; /* FSM current state */ + + uchar_t *linebuf; /* o/p raster data */ + +} DilloPng; + +#define DATASIZE (png->ipbufsize - png->ipbufstart) +#define BLACK 0 +#define WHITE 255 + +/* + * Forward declarations + */ +/* exported function */ +void *a_Png_image(const char *Type, void *Ptr, CA_Callback_t *Call, + void **Data); + + +static +void Png_error_handling(png_structp png_ptr, png_const_charp msg) +{ + DilloPng *png; + + DEBUG_MSG(6, "Png_error_handling: %s\n", msg); + png = png_get_error_ptr(png_ptr); + + png->error = 1; + png->state = IS_finished; + + longjmp(png->jmpbuf, 1); +} + +static void +Png_datainfo_callback(png_structp png_ptr, png_infop info_ptr) +{ + DilloPng *png; + int color_type; + int bit_depth; + int interlace_type; + uint_t i; + double gamma; + + DEBUG_MSG(5, "Png_datainfo_callback:\n"); + + png = png_get_progressive_ptr(png_ptr); + dReturn_if_fail (png != NULL); + + png_get_IHDR(png_ptr, info_ptr, &png->width, &png->height, + &bit_depth, &color_type, &interlace_type, NULL, NULL); + + DEBUG_MSG(5, "Png_datainfo_callback: png->width = %ld\n" + "Png_datainfo_callback: png->height = %ld\n", + png->width, png->height); + + /* we need RGB/RGBA in the end */ + if (color_type == PNG_COLOR_TYPE_PALETTE && bit_depth <= 8) { + /* Convert indexed images to RGB */ + png_set_expand (png_ptr); + } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { + /* Convert grayscale to RGB */ + png_set_expand (png_ptr); + } else if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS)) { + /* We have transparency header, convert it to alpha channel */ + png_set_expand(png_ptr); + } else if (bit_depth < 8) { + png_set_expand(png_ptr); + } + + if (bit_depth == 16) { + png_set_strip_16(png_ptr); + } + + /* Get and set gamma information. Beware: gamma correction 2.2 will + only work on PC's. todo: select screen gamma correction for other + platforms. */ + if (png_get_gAMA(png_ptr, info_ptr, &gamma)) + png_set_gamma(png_ptr, 2.2, gamma); + + /* Convert gray scale to RGB */ + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { + png_set_gray_to_rgb(png_ptr); + } + + /* Interlaced */ + if (interlace_type != PNG_INTERLACE_NONE) { + png->passes = png_set_interlace_handling(png_ptr); + } + + /* get libpng to update it's state */ + png_read_update_info(png_ptr, info_ptr); + + png_get_IHDR(png_ptr, info_ptr, &png->width, &png->height, + &bit_depth, &color_type, &interlace_type, NULL, NULL); + + png->rowbytes = png_get_rowbytes(png_ptr, info_ptr); + png->channels = png_get_channels(png_ptr, info_ptr); + + /* init Dillo specifics */ + DEBUG_MSG(5, "Png_datainfo_callback: rowbytes = %d\n" + "Png_datainfo_callback: width = %ld\n" + "Png_datainfo_callback: height = %ld\n", + png->rowbytes, png->width, png->height); + + png->image_data = (uchar_t *) dMalloc(png->rowbytes * png->height); + png->row_pointers = (uchar_t **) dMalloc(png->height * sizeof(uchar_t *)); + + for (i = 0; i < png->height; i++) + png->row_pointers[i] = png->image_data + (i * png->rowbytes); + + png->linebuf = dMalloc(3 * png->width); + + /* Initialize the dicache-entry here */ + a_Dicache_set_parms(png->url, png->version, png->Image, + (uint_t)png->width, (uint_t)png->height, + DILLO_IMG_TYPE_RGB); +} + +static void + Png_datarow_callback(png_structp png_ptr, png_bytep new_row, + png_uint_32 row_num, int pass) +{ + DilloPng *png; + uint_t i; + + if (!new_row) /* work to do? */ + return; + + DEBUG_MSG(5, "Png_datarow_callback: row_num = %ld\n", row_num); + + png = png_get_progressive_ptr(png_ptr); + + png_progressive_combine_row(png_ptr, png->row_pointers[row_num], new_row); + + switch (png->channels) { + case 3: + a_Dicache_write(png->Image, png->url, png->version, + png->image_data + (row_num * png->rowbytes), + 0, (uint_t)row_num); + break; + case 4: + { + /* todo: get the backgound color from the parent + * of the image widget -- Livio. */ + int a, bg_red, bg_green, bg_blue; + uchar_t *pl = png->linebuf; + uchar_t *data = png->image_data + (row_num * png->rowbytes); + + /* todo: maybe change prefs.bg_color to `a_Dw_widget_get_bg_color`, + * when background colors are correctly implementated */ + bg_blue = (png->Image->bg_color) & 0xFF; + bg_green = (png->Image->bg_color>>8) & 0xFF; + bg_red = (png->Image->bg_color>>16) & 0xFF; + + for (i = 0; i < png->width; i++) { + a = *(data+3); + + if (a == 255) { + *(pl++) = *(data++); + *(pl++) = *(data++); + *(pl++) = *(data++); + data++; + } else if (a == 0) { + *(pl++) = bg_red; + *(pl++) = bg_green; + *(pl++) = bg_blue; + data += 4; + } else { + png_composite(*(pl++), *(data++), a, bg_red); + png_composite(*(pl++), *(data++), a, bg_green); + png_composite(*(pl++), *(data++), a, bg_blue); + data++; + } + } + a_Dicache_write(png->Image, png->url, png->version, + png->linebuf, 0, (uint_t)row_num); + break; + } + default: + MSG("Png_datarow_callback: unexpected number of channels = %d\n", + png->channels); + abort(); + } +} + +static void + Png_dataend_callback(png_structp png_ptr, png_infop info_ptr) +{ + DilloPng *png; + + DEBUG_MSG(5, "Png_dataend_callback:\n"); + + png = png_get_progressive_ptr(png_ptr); + png->state = IS_finished; +} + + +/* + * Op: Operation to perform. + * If (Op == 0) + * start or continue processing an image if image data exists. + * else + * terminate processing, cleanup any allocated memory, + * close down the decoding process. + * + * Client->CbData : pointer to previously allocated DilloPng work area. + * This holds the current state of the image processing and is saved + * across calls to this routine. + * Client->Buf : Pointer to data start. + * Client->BufSize : the size of the data buffer. + * + * You have to keep track of where you are in the image data and + * how much has been processed. + * + * It's entirely possible that you will not see the end of the data. The + * user may terminate transfer via a Stop button or there may be a network + * failure. This means that you can't just wait for all the data to be + * presented before starting conversion and display. + */ +static void Png_callback(int Op, CacheClient_t *Client) +{ + DilloPng *png = Client->CbData; + + if (Op) { + /* finished - free up the resources for this image */ + a_Dicache_close(png->url, png->version, Client); + dFree(png->image_data); + dFree(png->row_pointers); + dFree(png->linebuf); + + if (setjmp(png->jmpbuf)) + MSG_WARN("PNG: can't destroy read structure\n"); + else if (png->png_ptr) + png_destroy_read_struct(&png->png_ptr, &png->info_ptr, NULL); + dFree(png); + return; + } + + /* Let's make some sound if we have been called with no data */ + dReturn_if_fail ( Client->Buf != NULL && Client->BufSize > 0 ); + + DEBUG_MSG(5, "Png_callback BufSize = %d\n", Client->BufSize); + + /* Keep local copies so we don't have to pass multiple args to + * a number of functions. */ + png->ipbuf = Client->Buf; + png->ipbufsize = Client->BufSize; + + /* start/resume the FSM here */ + while (png->state != IS_finished && DATASIZE) { + DEBUG_MSG(5, "State = %s\n", prog_state_name[png->state]); + + switch (png->state) { + case IS_init: + if (DATASIZE < 8) { + return; /* need MORE data */ + } + /* check the image signature - DON'T update ipbufstart! */ + if (!png_check_sig(png->ipbuf, DATASIZE)) { + /* you lied to me about it being a PNG image */ + png->state = IS_finished; + break; + } + /* OK, it looks like a PNG image, lets do some set up stuff */ + png->png_ptr = png_create_read_struct( + PNG_LIBPNG_VER_STRING, + png, + (png_error_ptr)Png_error_handling, + (png_error_ptr)Png_error_handling); + dReturn_if_fail (png->png_ptr != NULL); + png->info_ptr = png_create_info_struct(png->png_ptr); + dReturn_if_fail (png->info_ptr != NULL); + + setjmp(png->jmpbuf); + if (!png->error) { + png_set_progressive_read_fn( + png->png_ptr, + png, + Png_datainfo_callback, /* performs local init functions */ + Png_datarow_callback, /* performs per row action */ + Png_dataend_callback); /* performs cleanup actions */ + png->state = IS_nextdata; + } + break; + + case IS_nextdata: + if (setjmp(png->jmpbuf)) { + png->state = IS_finished; + } else if (!png->error) { + png_process_data( png->png_ptr, + png->info_ptr, + png->ipbuf + png->ipbufstart, + (png_size_t)DATASIZE); + + png->ipbufstart += DATASIZE; + } + break; + + default: + MSG_WARN("PNG decoder: bad state = %d\n", png->state); + abort(); + } + } +} + +/* + * Create the image state data that must be kept between calls + */ +static DilloPng *Png_new(DilloImage *Image, DilloUrl *url, int version) +{ + DilloPng *png = dNew0(DilloPng, 1); + + png->Image = Image; + png->url = url; + png->version = version; + png->error = 0; + png->ipbuf = NULL; + png->ipbufstart = 0; + png->ipbufsize = 0; + png->state = IS_init; + png->linebuf = NULL; + png->image_data = NULL; + png->row_pointers = NULL; + + return png; +} + +/* + * MIME handler for "image/png" type + * (Sets Png_callback or a_Dicache_callback as the cache-client) + */ +void *a_Png_image(const char *Type, void *Ptr, CA_Callback_t *Call, + void **Data) +{ +/* + * Type: MIME type + * Ptr: points to a Web structure + * Call: Dillo calls this with more data/eod + * Data: raw image data + */ + + DilloWeb *web = Ptr; + DICacheEntry *DicEntry; + + DEBUG_MSG(5, "a_Png_image: Type = %s\n" + "a_Png_image: libpng - Compiled %s; using %s.\n" + "a_Png_image: zlib - Compiled %s; using %s.\n", + Type, PNG_LIBPNG_VER_STRING, png_libpng_ver, + ZLIB_VERSION, zlib_version); + + if (!web->Image) + web->Image = a_Image_new(0, 0, NULL, prefs.bg_color); + + /* Add an extra reference to the Image (for dicache usage) */ + a_Image_ref(web->Image); + + DicEntry = a_Dicache_get_entry(web->url); + if (!DicEntry) { + /* Let's create an entry for this image... */ + DicEntry = a_Dicache_add_entry(web->url); + + /* ... and let the decoder feed it! */ + *Data = Png_new(web->Image, DicEntry->url, DicEntry->version); + *Call = (CA_Callback_t) Png_callback; + } else { + /* Let's feed our client from the dicache */ + a_Dicache_ref(DicEntry->url, DicEntry->version); + *Data = web->Image; + *Call = (CA_Callback_t) a_Dicache_callback; + } + return (web->Image->dw); +} + +#endif /* ENABLE_PNG */ |