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https://github.com/netsurf-browser/netsurf
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[project @ 2004-04-17 20:50:33 by rjw]
Fixed animation disposal handling. svn path=/import/netsurf/; revision=790
This commit is contained in:
Richard Wilson
parent
6f5dd247ad
commit
dc510627d9
126
riscos/gifread.c
126
riscos/gifread.c
@ -84,6 +84,9 @@ static int curbit, lastbit, get_done, last_byte;
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static int return_clear;
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static int zero_data_block = FALSE;
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/* Whether to clear the decoded image rather than plot
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*/
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static int clear_image = FALSE;
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/* Initialises any workspace held by the animation and attempts to decode
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@ -153,12 +156,12 @@ int gif_initialise(struct gif_animation *gif) {
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*/
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gif->width = 0; // Can't trust the supplied value
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gif->height = 0; // Can't trust the supplied value
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// gif->width = (gif_data[0] | (gif_data[1] << 8));
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// gif->height = (gif_data[2] | (gif_data[3] << 8));
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gif->global_colours = (gif_data[4] & 0x80);
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gif->colour_table_size = (2 << (gif_data[4] & 0x07));
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gif->background_colour = gif_data[5];
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gif->aspect_ratio = gif_data[6];
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gif->dirty_frame = -1;
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gif->dirty_plot = 0;
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gif_data += 7;
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/* Allocate some data irrespective of whether we've got any colour tables. We
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@ -513,20 +516,33 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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unsigned int *frame_data = 0; // Set to 0 for no warnings
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unsigned int *frame_scanline;
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unsigned int extension_size;
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unsigned int background_action;
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int transparency_index = -1;
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unsigned int transparent_colour = 0; // Set to 0 for no warnings
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unsigned int save_buffer_position;
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unsigned int frame_data_size;
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unsigned int return_value = 0;
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unsigned int x, y, decode_y;
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unsigned int block_size;
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int colour;
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unsigned int more_images;
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/* Ensure we have a frame to decode
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*/
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if (frame > gif->frame_count_partial) return GIF_INSUFFICIENT_DATA;
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if (frame == gif->decoded_frame) return 0;
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if ((!clear_image) && (frame == gif->decoded_frame)) return 0;
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/* If the previous frame was dirty, remove it
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*/
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if (!clear_image) {
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if (gif->decoded_frame == gif->dirty_frame) {
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clear_image = TRUE;
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if (frame != 0) gif_decode_frame(gif, gif->dirty_frame);
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clear_image = FALSE;
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gif->dirty_plot = 1;
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} else {
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gif->dirty_plot = 0;
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}
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gif->dirty_frame = -1;
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}
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/* Get the start of our frame data and the end of the GIF data
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*/
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@ -543,10 +559,12 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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produce errors.
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*/
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frame_data = (unsigned int*)((char *)gif->frame_image + sizeof(osspriteop_header));
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if (!clear_image) {
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if ((frame == 0) || (gif->decoded_frame == 0xffffffff)) {
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memset((char*)frame_data, 0x00, gif->width * gif->height * sizeof(int));
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}
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gif->decoded_frame = frame;
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}
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/* Save the buffer position
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*/
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@ -555,7 +573,7 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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/* We've got to do this more than one time if we've got multiple images
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*/
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gif->background_action = 0;
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background_action = 0;
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more_images = 1;
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while (more_images != 0) {
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@ -575,12 +593,13 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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/* Check we've enough data for the extension then header
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*/
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if ((gif_end - gif_data) < (int)(extension_size + 13)) return GIF_INSUFFICIENT_FRAME_DATA;
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/* Graphic control extension - store the frame delay.
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*/
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if (gif_data[1] == 0xf9) {
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flags = gif_data[3];
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if (flags & 0x01) transparency_index = gif_data[6];
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gif->background_action = ((flags & 0x1c) >> 2);
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background_action = ((flags & 0x1c) >> 2);
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more_images = ((gif_data[4] | (gif_data[5] << 8)) == 0);
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}
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/* Move to the first sub-block
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@ -603,7 +622,6 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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offset_y = gif_data[3] | (gif_data[4] << 8);
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width = gif_data[5] | (gif_data[6] << 8);
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height = gif_data[7] | (gif_data[8] << 8);
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// LOG(("Decoding %ix%i at offset (%i,%i)", width, height, offset_x, offset_y));
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/* Boundary checking - shouldn't ever happen except unless the data has been
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modified since initialisation.
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@ -623,28 +641,34 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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gif_data += 10;
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gif_bytes = (int)(gif_end - gif_data);
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/* Initialise our sprite to be totally transparent if we should
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*/
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// gif->frame_offset_x = offset_x;
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// gif->frame_offset_y = offset_y;
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// gif->frame_image->width = width;
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// gif->frame_image->height = height;
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/* Set up the colour table
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*/
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if (flags & 0x80) {
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// LOG(("Found local colour table"));
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if (gif_bytes < (int)(3 * colour_table_size)) return GIF_INSUFFICIENT_FRAME_DATA;
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colour_table = gif->local_colour_table;
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if (!clear_image) {
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for (index = 0; index < colour_table_size; index++) {
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colour_table[index] = gif_data[0] | (gif_data[1] << 8) |
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(gif_data[2] << 16) | 0xff000000;
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gif_data += 3;
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}
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} else {
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gif_data += 3 * colour_table_size;
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}
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gif_bytes = (int)(gif_end - gif_data);
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} else {
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colour_table = gif->global_colour_table;
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}
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/* If we are clearing the image we just clear, if not decode
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*/
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if (!clear_image) {
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/* Set our dirty status
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*/
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if ((background_action == 2) || (background_action == 3)) {
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gif->dirty_frame = frame;
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}
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/* Initialise the LZW decoding
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*/
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set_code_size = gif_data[0];
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@ -663,36 +687,8 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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return_clear = 1;
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stack_pointer = stack;
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/* Set the transparent colour as transparent
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*/
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if (transparency_index >= 0) {
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transparent_colour = colour_table[transparency_index];
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colour_table[transparency_index] = 0x00000000;
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}
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/* Decompress the data
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*/
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if ((gif->background_action == 2) || (gif->background_action == 3)) {
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frame_data_size = width * height;
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for (y = 0; y < height; y++) {
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if (interlace) {
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decode_y = gif_interlaced_line(height, y) + offset_y;
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} else {
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decode_y = y + offset_y;
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}
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frame_scanline = frame_data + offset_x + (decode_y * gif->width);
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for (x = 0; x < width; x++) {
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if ((colour = gif_read_LZW(gif)) >= 0) {
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*frame_scanline++ = colour_table[colour];
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} else {
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LOG(("%i bytes of %i read", index, frame_data_size));
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return_value = GIF_INSUFFICIENT_FRAME_DATA;
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goto gif_decode_frame_exit;
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}
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}
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}
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} else {
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frame_data_size = width * height;
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for (y = 0; y < height; y++) {
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if (interlace) {
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decode_y = gif_interlaced_line(height, y) + offset_y;
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@ -708,21 +704,39 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
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*frame_scanline++ = colour_table[colour];
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}
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} else {
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LOG(("%i bytes of %i read", index, frame_data_size));
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return_value = GIF_INSUFFICIENT_FRAME_DATA;
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goto gif_decode_frame_exit;
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}
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}
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}
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} else {
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/* Clear our frame
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*/
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if ((background_action == 2) || (background_action == 3)) {
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for (y = 0; y < height; y++) {
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frame_scanline = frame_data + offset_x + ((offset_y + y) * gif->width);
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memset(frame_scanline, 0x00, width * 4);
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}
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}
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/* Repeatedly skip blocks until we get a zero block or run out of data
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*/
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gif_bytes = gif->buffer_size - gif->buffer_position;
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gif_data = gif->gif_data + gif->buffer_size;
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block_size = 0;
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while (block_size != 1) {
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/* Skip the block data
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*/
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block_size = gif_data[0] + 1;
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if ((gif_bytes -= block_size) < 0) {
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return_value = GIF_INSUFFICIENT_FRAME_DATA;
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goto gif_decode_frame_exit;
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}
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gif_data += block_size;
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}
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}
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gif_decode_frame_exit:
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/* Unset the transparent colour
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*/
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if (transparency_index >= 0) {
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colour_table[transparency_index] = transparent_colour;
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}
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/* Check for end of data
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*/
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gif_bytes = gif->buffer_size - gif->buffer_position;
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@ -748,14 +762,6 @@ static unsigned int gif_interlaced_line(unsigned int height, unsigned int y) {
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if ((y << 2) < (height - 2)) return (y << 2) + 2;
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y -= ((height + 1) >> 2);
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return (y << 1) + 1;
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/* if ((y & 7) == 0) return (y >> 3);
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offset = (height + 7) >> 3;
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if ((y & 7) == 4) return offset + ((y - 4) >> 3);
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offset += (height + 3) >> 3;
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if ((y & 3) == 2) return offset + ((y - 2) >> 2);
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return offset + ((height + 1) >> 2) + ((y - 1) >> 1);
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*/
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}
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/* Releases any workspace held by the animation
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@ -63,11 +63,8 @@ typedef struct gif_animation {
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/* Decoded frame data
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*/
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// unsigned int frame_offset_x;
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// unsigned int frame_offset_y;
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// unsigned int frame_width;
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// unsigned int frame_height;
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unsigned int background_action;
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unsigned int dirty_plot; // Frame needs background erasing
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unsigned int dirty_frame; // Frame needs erasing before next
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osspriteop_header *frame_image;
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} gif_animation;
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