diff --git a/src/fileformats.c b/src/fileformats.c
index 52f073ab..61a2e9b0 100644
--- a/src/fileformats.c
+++ b/src/fileformats.c
@@ -3851,38 +3851,56 @@ void Save_ICO(T_IO_Context * context)
//////////////////////////////////// GIF ////////////////////////////////////
-typedef struct
-{
- word Width; // Width of the complete image area
- word Height; // Height of the complete image area
- byte Resol; // Informations about the resolution (and other)
- byte Backcol; // Proposed background color
- byte Aspect; // Informations about aspect ratio (and other)
-} T_GIF_LSDB; // Logical Screen Descriptor Block
+/**
+ * @defgroup GIF GIF format
+ * Graphics Interchange Format
+ *
+ * The GIF format uses LZW compression and stores indexed color pictures
+ * up to 256 colors. It has the ability to store several pictures in the same
+ * file : GrafX2 takes advantage of this feature for storing layered images
+ * and animations.
+ *
+ * GrafX2 implements GIF89a :
+ * https://www.w3.org/Graphics/GIF/spec-gif89a.txt
+ *
+ * @{
+ */
+/// Logical Screen Descriptor Block
typedef struct
{
- word Pos_X; // X offset where the image should be pasted
- word Pos_Y; // Y offset where the image should be pasted
- word Image_width; // Width of image
- word Image_height; // Height of image
- byte Indicator; // Misc image information
- byte Nb_bits_pixel; // Nb de bits par pixel
-} T_GIF_IDB; // Image Descriptor Block
+ word Width; ///< Width of the complete image area
+ word Height; ///< Height of the complete image area
+ byte Resol; ///< Informations about the resolution (and other)
+ byte Backcol; ///< Proposed background color
+ byte Aspect; ///< Informations about aspect ratio. Ratio = (Aspect + 15) / 64
+} T_GIF_LSDB;
+/// Image Descriptor Block
typedef struct
{
- byte Block_identifier; // 0x21
- byte Function; // 0xF9
- byte Block_size; // 4
- byte Packed_fields; // 11100000 : Reserved
- // 00011100 : Disposal method
- // 00000010 : User input flag
- // 00000001 : Transparent flag
- word Delay_time; // Time for this frame to stay displayed
- byte Transparent_color; // Which color index acts as transparent
- word Block_terminator; // 0x00
-} T_GIF_GCE; // Graphic Control Extension
+ word Pos_X; ///< X offset where the image should be pasted
+ word Pos_Y; ///< Y offset where the image should be pasted
+ word Image_width; ///< Width of image
+ word Image_height; ///< Height of image
+ byte Indicator; ///< Misc image information
+ byte Nb_bits_pixel; ///< Nb de bits par pixel
+} T_GIF_IDB;
+
+/// Graphic Control Extension
+typedef struct
+{
+ byte Block_identifier; ///< 0x21
+ byte Function; ///< 0xF9
+ byte Block_size; ///< 4
+ byte Packed_fields; ///< 11100000 : Reserved
+ ///< 00011100 : Disposal method
+ ///< 00000010 : User input flag
+ ///< 00000001 : Transparent flag
+ word Delay_time; ///< Time for this frame to stay displayed
+ byte Transparent_color; ///< Which color index acts as transparent
+ word Block_terminator; ///< 0x00
+} T_GIF_GCE;
enum DISPOSAL_METHOD
{
@@ -3892,8 +3910,9 @@ enum DISPOSAL_METHOD
DISPOSAL_METHOD_RESTORE_PREVIOUS = 3,
};
-// -- Tester si un fichier est au format GIF --------------------------------
+/// @ingroup loadsaveformats GIF
+/// Test if a file is GIF format
void Test_GIF(T_IO_Context * context, FILE * file)
{
char signature[6];
@@ -3903,6 +3922,7 @@ void Test_GIF(T_IO_Context * context, FILE * file)
if (Read_bytes(file,signature,6))
{
+ /// checks if the signature (6 first bytes) is either GIF87a or GIF89a
if ((!memcmp(signature,"GIF87a",6))||(!memcmp(signature,"GIF89a",6)))
File_error=0;
}
@@ -3911,6 +3931,7 @@ void Test_GIF(T_IO_Context * context, FILE * file)
// -- Lire un fichier au format GIF -----------------------------------------
+/// @todo avoid using global variables, define a "GIF context" instead
// Définition de quelques variables globales au chargement du GIF87a
word GIF_nb_bits; // Nb de bits composants un code complet
word GIF_remainder_bits; // Nb de bits encore dispos dans GIF_last_byte
@@ -3924,9 +3945,8 @@ word GIF_finished_interlaced_image; // L'image entrelacée est finie de charger
word GIF_pass; // index de passe de l'image entrelacée
FILE *GIF_file; // L'handle du fichier
-// -- Lit le code à GIF_nb_bits suivant --
-
-word GIF_get_next_code(void)
+/// Reads the next code (GIF_nb_bits bits)
+static word GIF_get_next_code(void)
{
word nb_bits_to_process=GIF_nb_bits;
word nb_bits_processed =0;
@@ -3964,12 +3984,11 @@ word GIF_get_next_code(void)
return GIF_current_code;
}
-// -- Affiche un nouveau pixel --
-
-void GIF_new_pixel(T_IO_Context * context, T_GIF_IDB *idb, int is_transparent, byte color)
+/// Put a new pixel
+static void GIF_new_pixel(T_IO_Context * context, T_GIF_IDB *idb, int is_transparent, byte color)
{
if (!is_transparent || color!=context->Transparent_color)
- Set_pixel(context, idb->Pos_X+GIF_pos_X, idb->Pos_Y+GIF_pos_Y,color);
+ Set_pixel(context, idb->Pos_X+GIF_pos_X, idb->Pos_Y+GIF_pos_Y,color);
GIF_pos_X++;
@@ -4010,6 +4029,8 @@ void GIF_new_pixel(T_IO_Context * context, T_GIF_IDB *idb, int is_transparent, b
}
+/// @ingroup loadsaveformats GIF
+/// Load GIF file
void Load_GIF(T_IO_Context * context)
{
int image_mode = -1;
@@ -4531,9 +4552,8 @@ void Load_GIF(T_IO_Context * context)
int GIF_stop; // "On peut arrêter la sauvegarde du fichier"
byte GIF_buffer[256]; // buffer d'écriture de bloc de données compilées
- // -- Vider le buffer GIF dans le buffer KM --
-
- void GIF_empty_buffer(void)
+ /// Flush ::GIF_buffer
+ static void GIF_empty_buffer(void)
{
word index;
@@ -4548,9 +4568,8 @@ void Load_GIF(T_IO_Context * context)
}
}
- // -- Ecrit un code à GIF_nb_bits --
-
- void GIF_set_code(word Code)
+ /// Write a code (GIF_nb_bits bits)
+ static void GIF_set_code(word Code)
{
word nb_bits_to_process=GIF_nb_bits;
word nb_bits_processed =0;
@@ -4583,9 +4602,8 @@ void Load_GIF(T_IO_Context * context)
}
- // -- Lire le pixel suivant --
-
- byte GIF_next_pixel(T_IO_Context *context, T_GIF_IDB *idb)
+ /// Read the next pixel
+ static byte GIF_next_pixel(T_IO_Context *context, T_GIF_IDB *idb)
{
byte temp;
@@ -4602,7 +4620,8 @@ void Load_GIF(T_IO_Context * context)
}
-
+/// @ingroup loadsaveformats GIF
+/// Save a GIF file
void Save_GIF(T_IO_Context * context)
{
word * alphabet_prefix; // Table des préfixes des codes
@@ -4704,13 +4723,18 @@ void Save_GIF(T_IO_Context * context)
{
// La palette a été correctement écrite.
- // Ecriture de la transparence
- //Write_bytes(GIF_file,"\x21\xF9\x04\x01\x00\x00\xNN\x00",8);
-
- // "Netscape" animation extension
- // Write_bytes(GIF_file,"\x21\xFF\x0BNETSCAPE2.0\x03\xLL\xSS\xSS\x00",19);
- // LL : 01 to loop
- // SSSS : number of loops
+ /// - "Netscape" animation extension :
+ ///
+ /// 0x21 Extension Label
+ /// 0xFF Application Extension Label
+ /// 0x0B Block Size
+ /// "NETSCAPE" Application Identifier (8 bytes)
+ /// "2.0" Application Authentication Code (3 bytes)
+ /// 0x03 Sub-block Data Size
+ /// 0xLL 01 to loop
+ /// 0xSSSS (little endian) number of loops, 0 means infinite loop
+ /// 0x00 Block terminator
+ /// see http://www.vurdalakov.net/misc/gif/netscape-looping-application-extension
if (context->Type == CONTEXT_MAIN_IMAGE && Main.backups->Pages->Image_mode == IMAGE_MODE_ANIMATION)
{
if (context->Nb_layers>1)
@@ -4718,16 +4742,30 @@ void Save_GIF(T_IO_Context * context)
}
else if (context->Type == CONTEXT_MAIN_IMAGE && Main.backups->Pages->Image_mode > IMAGE_MODE_ANIMATION)
{
+ /// - GrafX2 extension to store ::IMAGE_MODES :
+ ///
+ /// 0x21 Extension Label
+ /// 0xFF Application Extension Label
+ /// 0x0B Block Size
+ /// "GFX2MODE" Application Identifier (8 bytes)
+ /// "2.6" Application Authentication Code (3 bytes)
+ /// 0xll Sub-block Data Size
+ /// string label
+ /// 0x00 Block terminator
+ /// @see Constraint_mode_label()
const char * label = Constraint_mode_label(Main.backups->Pages->Image_mode);
- size_t len = strlen(label);
- // Write extension for storing IMAGE_MODE
- Write_byte(GIF_file,0x21); // Extension Introducer
- Write_byte(GIF_file,0xff); // Extension Label
- Write_byte(GIF_file, 11); // Block size
- Write_bytes(GIF_file, "GFX2MODE2.6", 11); // Application Identifier + Appl. Authentication Code
- Write_byte(GIF_file, (byte)len); // Block size
- Write_bytes(GIF_file, label, len); // Data
- Write_byte(GIF_file, 0); // Block terminator
+ if (label != NULL)
+ {
+ size_t len = strlen(label);
+ // Write extension for storing IMAGE_MODE
+ Write_byte(GIF_file,0x21); // Extension Introducer
+ Write_byte(GIF_file,0xff); // Extension Label
+ Write_byte(GIF_file, 11); // Block size
+ Write_bytes(GIF_file, "GFX2MODE2.6", 11); // Application Identifier + Appl. Authentication Code
+ Write_byte(GIF_file, (byte)len); // Block size
+ Write_bytes(GIF_file, label, len); // Data
+ Write_byte(GIF_file, 0); // Block terminator
+ }
}
// Ecriture du commentaire
@@ -4737,7 +4775,20 @@ void Save_GIF(T_IO_Context * context)
Write_byte(GIF_file,strlen(context->Comment));
Write_bytes(GIF_file,context->Comment,strlen(context->Comment)+1);
}
- // Write cycling colors
+ /// - "CRNG" Color cycing extension :
+ ///
+ /// 0x21 Extension Label
+ /// 0xFF Application Extension Label
+ /// 0x0B Block Size
+ /// "CRNG\0\0\0\0" "CRNG" Application Identifier (8 bytes)
+ /// "1.0" Application Authentication Code (3 bytes)
+ /// 0xll Sub-block Data Size (6 bytes per color cycle)
+ /// For each color cycle :
+ /// 0xRRRR (big endian) Rate
+ /// 0xFFFF (big endian) Flags
+ /// 0xSS start (lower color index)
+ /// 0xEE end (higher color index)
+ /// 0x00 Block terminator
if (context->Color_cycles)
{
int i;
@@ -5050,14 +5101,21 @@ void Save_GIF(T_IO_Context * context)
// After writing all layers
if (!File_error)
{
- // If requested, write a specific extension for storing
- // original file path.
- // This is used by the backup system.
- // The format is :
- // 21 FF 0B G F X 2 P A T H 00 00 00
- //
- //
- // 00
+ /// - If requested, write a specific extension for storing
+ /// original file path.
+ /// This is used by the backup system.
+ /// The format is :
+ ///
+ /// 0x21 Extension Label
+ /// 0xFF Application Extension Label
+ /// 0x0B Block Size
+ /// "GFX2PATH" "GFX2PATH" Application Identifier (8 bytes)
+ /// "\0\0\0" Application Authentication Code (3 bytes)
+ /// 0xll Sub-block Data Size : path size (including null)
+ /// "..path.." path (null-terminated)
+ /// 0xll Sub-block Data Size : filename size (including null)
+ /// "..file.." file name (null-terminated)
+ /// 0x00 Block terminator
if (context->Original_file_name != NULL
&& context->Original_file_directory != NULL)
{
@@ -5108,6 +5166,7 @@ void Save_GIF(T_IO_Context * context)
}
+/* @} */
//////////////////////////////////// PCX ////////////////////////////////////