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PNG: properly use png_set_read_user_chunk_fn()

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Also add Doxygen for PNG code
This commit is contained in:
Thomas Bernard 2018-12-11 12:23:32 +01:00
parent 337129f760
commit 4153c315be
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GPG Key ID: 0FF11B67A5C0863C
1 changed files with 27 additions and 20 deletions
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47
src/fileformats.c
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@ -6016,7 +6016,9 @@ void Save_XPM(T_IO_Context* context)
#ifndef __no_pnglib__ #ifndef __no_pnglib__
// -- Tester si un fichier est au format PNG -------------------------------- /// Test for PNG format
///
/// The 8 byte signature at the start of file is tested
void Test_PNG(T_IO_Context * context, FILE * file) void Test_PNG(T_IO_Context * context, FILE * file)
{ {
byte png_header[8]; byte png_header[8];
@ -6032,22 +6034,27 @@ void Test_PNG(T_IO_Context * context, FILE * file)
} }
} }
/// Used by a callback in Load_PNG /// Callback to handle our private chunks
T_IO_Context * PNG_current_context; ///
/// We have one private chunk at the moment :
int PNG_read_unknown_chunk(png_structp ptr, png_unknown_chunkp chunk) /// - "crNg" which is similar to a CRNG chunk in an IFF file
static int PNG_read_unknown_chunk(png_structp ptr, png_unknown_chunkp chunk)
{ {
(void)ptr; // unused T_IO_Context * context;
// png_unknown_chunkp members: // png_unknown_chunkp members:
// png_byte name[5]; // png_byte name[5];
// png_byte *data; // png_byte *data;
// png_size_t size; // png_size_t size;
context = (T_IO_Context *)png_get_user_chunk_ptr(ptr);
GFX2_Log(GFX2_DEBUG, "PNG private chunk '%s' :\n", chunk->name);
GFX2_LogHexDump(GFX2_DEBUG, "", chunk->data, 0, chunk->size);
if (!strcmp((const char *)chunk->name, "crNg")) if (!strcmp((const char *)chunk->name, "crNg"))
{ {
// Color animation. Similar to a CRNG chunk in an IFF file.
unsigned int i; unsigned int i;
byte *chunk_ptr = chunk->data; const byte *chunk_ptr = chunk->data;
// Should be a multiple of 6 // Should be a multiple of 6
if (chunk->size % 6) if (chunk->size % 6)
@ -6081,12 +6088,12 @@ int PNG_read_unknown_chunk(png_structp ptr, png_unknown_chunkp chunk)
if (max_col<min_col) if (max_col<min_col)
SWAP_BYTES(min_col,max_col) SWAP_BYTES(min_col,max_col)
PNG_current_context->Cycle_range[i].Start=min_col; context->Cycle_range[i].Start=min_col;
PNG_current_context->Cycle_range[i].End=max_col; context->Cycle_range[i].End=max_col;
PNG_current_context->Cycle_range[i].Inverse=(flags&2)?1:0; context->Cycle_range[i].Inverse=(flags&2)?1:0;
PNG_current_context->Cycle_range[i].Speed=(flags&1) ? rate/78 : 0; context->Cycle_range[i].Speed=(flags&1) ? rate/78 : 0;
PNG_current_context->Color_cycles=i+1; context->Color_cycles=i+1;
} }
} }
@ -6097,7 +6104,7 @@ int PNG_read_unknown_chunk(png_structp ptr, png_unknown_chunkp chunk)
} }
// -- Lire un fichier au format PNG ----------------------------------------- /// Read PNG format file
static void Load_PNG_Sub(T_IO_Context * context, FILE * file) static void Load_PNG_Sub(T_IO_Context * context, FILE * file)
{ {
png_structp png_ptr; png_structp png_ptr;
@ -6113,7 +6120,6 @@ static void Load_PNG_Sub(T_IO_Context * context, FILE * file)
{ {
png_byte color_type; png_byte color_type;
png_byte bit_depth; png_byte bit_depth;
png_voidp user_chunk_ptr;
byte bpp; byte bpp;
// Setup a return point. If a pnglib loading error occurs // Setup a return point. If a pnglib loading error occurs
@ -6125,11 +6131,7 @@ static void Load_PNG_Sub(T_IO_Context * context, FILE * file)
png_set_sig_bytes(png_ptr, 8); png_set_sig_bytes(png_ptr, 8);
// Hook the handler for unknown chunks // Hook the handler for unknown chunks
user_chunk_ptr = png_get_user_chunk_ptr(png_ptr); png_set_read_user_chunk_fn(png_ptr, (png_voidp)context, &PNG_read_unknown_chunk);
png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr, &PNG_read_unknown_chunk);
// This is a horrid way to pass parameters, but we don't get
// much choice. PNG loader can't be reintrant.
PNG_current_context=context;
// Load file information // Load file information
png_read_info(png_ptr, info_ptr); png_read_info(png_ptr, info_ptr);
@ -6414,6 +6416,10 @@ static void Load_PNG_Sub(T_IO_Context * context, FILE * file)
} }
} }
/// Read PNG format files
///
/// just read/test the header and call Load_PNG_Sub()
void Load_PNG(T_IO_Context * context) void Load_PNG(T_IO_Context * context)
{ {
FILE *file; FILE *file;
@ -6441,6 +6447,7 @@ void Load_PNG(T_IO_Context * context)
File_error=1; File_error=1;
} }
/// Save a PNG file
void Save_PNG(T_IO_Context * context) void Save_PNG(T_IO_Context * context)
{ {
FILE *file; FILE *file;