NAME

XGetPixel − obtain a single pixel value from an image. 

Synopsis

unsigned long XGetPixel(ximage, x, y)
XImage *ximage;
int x;
int y;

Arguments

ximageSpecifies a pointer to the image. 

x

ySpecify the x and y coordinates of the pixel whose value is to be returned. 

Description

XGetPixel() returns the specified pixel from the named image.  The x and y coordinates are relative to the origin (upper left [0,0]) of the image).  The pixel value is returned in the normalized format (that is, the least-significant byte of the long is the least-significant byte of the pixel).  The x and y coordinates must be contained in the image.  For more information, see Volume One, Chapter 6, Drawing Graphics and Text. 

Structures

typedef struct _XImage {
int width, height;/* size of image */
int xoffset;/* number of pixels offset in X direction */
int format;/* XYBitmap, XYPixmap, ZPixmap */
char *data;/* pointer to image data */
int byte_order;/* data byte order, LSBFirst, MSBFirst */
int bitmap_unit;/* quant. of scan line 8, 16, 32 */
int bitmap_bit_order;/* LSBFirst, MSBFirst */
int bitmap_pad;/* 8, 16, 32 either XY or ZPixmap */
int depth;/* depth of image */
int bytes_per_line;/* accelerator to next line */
int bits_per_pixel;/* bits per pixel (ZPixmap) */
unsigned long red_mask;/* bits in z arrangment */
unsigned long green_mask;
unsigned long blue_mask;
char *obdata;/* hook for the object routines to hang on */
struct funcs {/* image manipulation routines */
    struct _XImage *(*create_image)();
        int (*destroy_image)();
    unsigned long (*get_pixel)();
    int (*put_pixel)();
    struct _XImage *(*sub_image)();
    int (*add_pixel)();
} f;
} XImage;

See Also

ImageByteOrder(), XAddPixel(), XCreateImage(), XDestroyImage(), XGetImage(), XGetSubImage(), XPutImage(), XPutPixel(), XSubImage(). 

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