gd.h

The data structure in which gd stores images.  gdImageCreate, gdImageCreateTrueColor and the various image file-loading functions return a pointer to this type, and the other functions expect to receive a pointer to this type as their first argument.

gdImagePtr is a pointer to gdImage.

(Previous versions of this library encouraged directly manipulating the contents ofthe struct but we are attempting to move away from this practice so the fields are no longer documented here.  If you need to poke at the internals of this struct, feel free to look at gd.h.)

Defines a point in a 2D coordinate system using floating point values. x - Floating point position (increase from left to right) y - Floating point Row position (increase from top to bottom)

Pointer to a gdPointF

See also

gdImageCreate, gdImageCreateTrueColor,

A font structure, containing the bitmaps of all characters in a font.  Used to declare the characteristics of a font.  Text-output functions expect these as their second argument, following the gdImagePtr argument.  <gdFontSmall> and <gdFontGetLarge> both return one.

You can provide your own font data by providing such a structure and the associated pixel array.  You can determine the width and height of a single character in a font by examining the w and h members of the structure.  If you will not be creating your own fonts, you will not need to concern yourself with the rest of the components of this structure.

Please see the files gdfontl.c and gdfontl.h for an example of the proper declaration of this structure.

typedef struct {
  // # of characters in font
  int nchars;
  // First character is numbered... (usually 32 = space)
  int offset;
  // Character width and height
  int w;
  int h;
  // Font data; array of characters, one row after another.
  // Easily included in code, also easily loaded from
  // data files.
  char *data;
} gdFont;

gdFontPtr is a pointer to gdFont.

Note: This interface is obsolete and kept only for *compatibility.  Use gdIOCtx instead.

Represents a source from which a PNG can be read.  Programmers who do not wish to read PNGs from a file can provide their own alternate input mechanism, using the gdImageCreateFromPngSource function.  See the documentation of that function for an example of the proper use of this type.

typedef struct {
        int (*source) (void *context, char *buffer, int len);
        void *context;
} gdSource, *gdSourcePtr;

The source function must return -1 on error, otherwise the number of bytes fetched.  0 is EOF, not an error!

’context’ will be passed to your source function.

A structure and associated pointer type used to pass additional parameters to the gdImageStringFTEx function.  See gdImageStringFTEx for the structure definition.

Thanks to Wez Furlong.

Represents a point in the coordinate space of the image; used by <gdImagePolygon>, <gdImageOpenPolygon> and <gdImageFilledPolygon> for polygon drawing.

typedef struct {
    int x, y;
} gdPoint, *gdPointPtr;

Note: This interface is obsolete and kept only for *compatibility.  Use gdIOCtx instead.

Represents a “sink” (destination) to which a PNG can be written.  Programmers who do not wish to write PNGs to a file can provide their own alternate output mechanism, using the <gdImagePngToSink> function.  See the documentation of that function for an example of the proper use of this type.

typedef struct {
    int (*sink) (void *context, char *buffer, int len);
    void *context;
} gdSink, *gdSinkPtr;

The sink function must return -1 on error, otherwise the number of bytes written, which must be equal to len.

context will be passed to your sink function.