GetPixel(3X) — DeltaWindows 1.3.3 Release 4 Version 4.3

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.

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

RETURNS

The pixel value.

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;