Display Images using OpenGL
[Image Package]

Classes
struct	DisplayAssoc
struct	OpenGLTextureStruct
	Structure holding information on OpenGL textures. More...
struct	_Gan_GLExt_Function_Pointers
	Structure to hold ARB OpenGL extension function pointers. More...
Defines
#define	QUIT   99
#define	GL_GLEXT_PROTOTYPES   1
#define	LARGEST_TEXTURE_TILE_SIZE   256
#define	gan_texGetProcAddress(name)   (*glXGetProcAddressARB)(name)
Typedefs
typedef OpenGLTextureStruct	Gan_OpenGLTextureStruct
	Structure holding information on OpenGL textures.
typedef _Gan_GLExt_Function_Pointers	Gan_GLExt_Function_Pointers
	Structure to hold ARB OpenGL extension function pointers.
Functions
Gan_Bool	gan_image_display (const Gan_Image *img)
	Displays an image using OpenGL.
Gan_Bool	gan_display_new_window (int height, int width, double zoom, char *name, int offset_r, int offset_c, int *window_id)
	Creates an OpenGL display window.
Gan_Bool	gan_display_new_window_array (int rows, int cols, int height, int width, double zoom, char *name, int offset_r, int offset_c, int *window_id, int **subwindow_id)
	Creates an OpenGL display window with subwindows.
void	gan_image_display_free_windows (void)
	Frees image display stuff.
Gan_Bool	gan_image_display_new_window (const Gan_Image *img, double zoom, char *name, int offset_r, int offset_c, int *window_idp)
	Displays an image using OpenGL.
void	gan_initialise_glext_func_ptrs (Gan_GLExt_Function_Pointers *pExtFnPtrs)
	Initialise OpenGL extension function pointer structure.
int	gan_check_glext_func_ptrs ()
	Return status of OpenGL extension function pointer structure, non-zero is error.
Gan_Bool	gan_build_openGL_textures_for_image (Gan_Image *pgiImage, Gan_OpenGLTextureStruct *pOGLTexStruct)
	Build a set of OpenGL texture tiles for an image.
void	gan_free_openGL_textures_for_image (Gan_OpenGLTextureStruct *pOGLTexStruct)
	Free OpenGL texture tiles for an image.
Gan_Bool	gan_render_openGL_textures_for_image (Gan_OpenGLTextureStruct *pOGLTexStruct)
	Render OpenGL texture tiles for an image.
Variables
Gan_List *	list = NULL

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Function Documentation

Gan_Bool gan_build_openGL_textures_for_image (  Gan_Image *  image, Gan_OpenGLTextureStruct *  pOGLTexStruct )

Build a set of OpenGL texture tiles for an image. Returns: GAN_TRUE on success, or GAN_FALSE on failure.

Gan_Bool gan_display_new_window (  int  height, int  width, double  zoom, char *  name, int  offset_r, int  offset_c, int *  window_id )

Creates an OpenGL display window. Parameters: height  The height images/graphics to be shown in the window width  The width of images/graphics to be shown in the window zoom  Zoom factor for image/graphics in the window name  A name for the window offset_r  Vertical offset of window from corner of screen offset_c  Horizontal offset of window from corner of screen window_id  Pointer to the OpenGL display window ID Returns: GAN_TRUE on success, GAN_FALSE on failure. Creates a new OpenGL window, with the given dimensions, zoom factor, name and screen offsets. Upon success, the ID of the new OpenGL window is passed back in the window_id pointer. See also: gan_display_new_window_array().

Gan_Bool gan_display_new_window_array (  int  rows, int  cols, int  height, int  width, double  zoom, char *  name, int  offset_r, int  offset_c, int *  window_id, int **  subwindow_id )

Creates an OpenGL display window with subwindows. Parameters: rows  Number of subwindows in window vertically cols  Number of subwindows in window horizontally height  The height images/graphics to be shown in the window width  The width of images/graphics to be shown in the window zoom  Zoom factor for image/graphics in the window name  A name for the window offset_r  Vertical offset of window from corner of screen offset_c  Horizontal offset of window from corner of screen window_id  Pointer to the main OpenGL display window ID subwindow_id  Pointer to the array of OpenGL subwindow IDs Returns: GAN_TRUE on success, GAN_FALSE on failure. Creates a new OpenGL window with the given name and screen offsets, and containing subwindows, each with the given dimensions and zoom factor, in an array of rows by cols subwindows. Upon success, the ID of the main OpenGL window created is passed back in the window_id pointer, and an array of rows by cols OpenGL subwindow IDs is passed back in subwindow_id. (*subwindow_id)[0], (*subwindow_id)[cols-1], (*subwindow_id)[rows*(cols-1)] and (*subwindow_id)[rows*cols-1] are the IDs for the top-left, top-right, bottom-left and bottom-right subwindows respectively. The subwindow_id array is dynamically allocated using malloc(). See also: gan_display_new_window().

Gan_Bool gan_image_display (  const Gan_Image *  img  )

Displays an image using OpenGL. Parameters: img  The image to display Returns: GAN_TRUE on success, GAN_FALSE on failure. Displays an image on the screen using the OpenGL function glDrawPixels(). Assumes that the graphics window has already been set up in a way similar to the procedure in gan_image_display_new_window(). See also: gan_image_display_new_window().

void gan_image_display_free_windows (  void   )

Frees image display stuff. Returns: No value. Call this function to free stored display images created by calls to gan_image_display_new_window(), just prior to exiting the program. See also: gan_image_display_new_window().

Gan_Bool gan_image_display_new_window (  const Gan_Image *  img, double  zoom, char *  name, int  offset_r, int  offset_c, int *  window_id )

Displays an image using OpenGL. Parameters: img  The image to display zoom  Zoom factor name  A name for the window offset_r  Vertical offset of window from corner of screen offset_c  Horizontal offset of window from corner of screen window_idp  Pointer to the OpenGL display window ID Returns: GAN_TRUE on success, GAN_FALSE on failure. Creates a new OpenGL window, with the given screen offset and zoom factor, and displays the provided image in the window. The image is copied, so this is not memory-efficient. Upon success, the ID of the new OpenGL window is passed back in the window_id pointer. See also: gan_image_display().

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