import (3) functionality for reading images from files

NAMEimport

- Image file format autodetection, reading and decoding routines.

AUTHOR

Sasha Vasko <sasha at aftercode dot net> libAfterImage/gamma

NAMESCREEN_GAMMA

- Defines default value for screen gamma correction.

SOURCE

#define SCREEN_GAMMA 2.2 #define DEFAULT_PNG_IMAGE_GAMMA 0.45455

libAfterImage/ASImageFileTypes

NAMEASImageFileTypes

- List of known image file formats.

SOURCE

typedef enum {
    ASIT_Xpm = 0,
    ASIT_ZCompressedXpm,
    ASIT_GZCompressedXpm,
    ASIT_Png,
    ASIT_Jpeg,
    ASIT_Xcf,
    ASIT_Ppm,
    ASIT_Pnm,
    ASIT_Bmp,
    ASIT_Ico,
    ASIT_Cur,
    ASIT_Gif,
    ASIT_Tiff,
    ASIT_XMLScript,
    ASIT_SVG,
    /* reserved for future implementation : */
    ASIT_Xbm,
    ASIT_Targa,
    ASIT_Supported = ASIT_Targa,
    ASIT_Pcx,
    ASIT_HTML,
    ASIT_XML,
    ASIT_Unknown }ASImageFileTypes;

libAfterImage/ASImageListEntry

NAMEASImageListEntry

- entry in linked list of images loaded from single directory.

SOURCE

typedef struct ASImageListEntryBuffer { #define ASILEB_Dirty (0x01<<0) #define ASILEB_Binary (0x01<<1)


    ASFlagType flags ; 


    size_t size ; 
    char  *data ; 
     }ASImageListEntryBuffer;

typedef struct ASImageListEntry { #define MAGIC_ASIMAGE_LIST_ENTRY 0xA3A311E4 #define IS_ASIMAGE_LIST_ENTRY(e) (((e)!=NULL)&&((e)->magic==MAGIC_ASIMAGE_LIST_ENTRY)&&((e)->ref_count>0))


    unsigned long magic ; 
    struct ASImageListEntry *prev, *next ;
    char   *name ;
    char   *fullfilename ;


    ASImageFileTypes    type;
    ASImage            *preview;

#ifndef _WIN32
    mode_t d_mode; #endif
    time_t d_mtime;
    off_t  d_size;      /* total size, in bytes */


    ASImageListEntryBuffer *buffer ; 


    int ref_count; }ASImageListEntry;

libAfterImage/import/file2ASImage()

NAMEfile2ASImage()

- load ASImage from file.

SYNOPSIS

ASImage *file2ASImage( const char *file, ASFlagType what,
                       double gamma,
                       unsigned int compression, ... );

INPUTS

file
- file name with or without directory name
what
- reserved for future use
gamma
- gamma value to be used to correct image
compression
- compression level of the resulting ASImage
...
- NULL terminated list of strings, representing arbitrary number of directories to be searched each.

RETURN VALUE

Pointer to ASImage structure holding image data on success. NULL on failure

DESCRIPTION

file2ASImage will attempt to interpret filename in the following way: 1)It will try to find file using unmodified filename in all the provided search paths. 2)It will attempt to append .gz and then .Z to the filename and find such file in all the provided search paths. 3)If filename ends with extension consisting of digits only - it will attempt to find file with this extension stripped off. On success this extension will be used to load subimage from the file with that number. Subimages are supported only for XCF, GIF, BMP, ICO and CUR files. After the file is found file2ASImage() attempts to detect file format, and if it is known it will load it into new ASImage structure.

EXAMPLE

asview.c: ASView.2 libAfterImage/import/get_asimage()

NAMEget_asimage()

- increment reference counter if file is already loaded, or load image from file.

SYNOPSIS

ASImage *get_asimage( ASImageManager* imageman, const char *file,
                      ASFlagType what, unsigned int compression );

INPUTS

imageman
- pointer to valid ASVisual structure.
file
- root window ID for the destination screen.
what
- full image file's name with path.
compression
-

RETURN VALUE

Pointer to ASImage structure holding image data on success. NULL on failure

DESCRIPTION

get_asimage will attempt check with the ASImageManager's list of load images, and if image with requested filename already exists - it will increment its reference count and return its pointer. Otherwise it will call file2ASImage() to load image from file. It will use PATH and gamma values from the ASImageManager to pass to file2ASImage(). If image is successfully loaded - it will be added to the ASImageManager's list and its pointer will be returned.

NAMEfile2pixmap()

- convinience function to load file into X Pixmap.

SYNOPSIS

Pixmap file2pixmap( struct ASVisual *asv, Window root,
                    const char *realfilename,
                    Pixmap *mask_out);

INPUTS

asv
- pointer to valid ASVisual structure.
root
- root window ID for the destination screen.
realfilename
- full image file's name with path.

RETURN VALUE

Pixmap ID of the X Pixmap filled with loaded image. If mask_out is not NULL it will point to image mask Pixmap ID if there is an alpha channel in image, None otherwise. On failure None will be returned.

DESCRIPTION

file2pixmap() will attempt to open specified file and autodetect its format. If format is known it will load it into ASImage first, and then convert it into X Pixmap. In case image has alpha channel - mask Pixmap will be produced if mask_out is not NULL.

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