Dali: Byte16Image -- C API

Header Files

#include <dvmbasic.h>

Type Definitions

Byte16Image

A Byte16Image is a buffer storing 2D array of shorts. Just like a ByteImage, a Byte16Image can be either physical or virtual.

    typedef struct Byte16Image {
        int width;
        int height;
        int x;
        int y;
        int parentWidth;
        unsigned char isVirtual;
        short *firstByte;
    } Byte16Image;

width

the width of the Byte16Image

height

the height of the Byte16Image

x

the x-offset of the top-left corner of the Byte16Image from it's parent.

y

the y-offset of the top-left corner of the Byte16Image from it's parent.

parentWidth

the width of the physical parent of this Byte16Image. (should be called rootWidth since the parent might not be physical)

virtual

1 iff the Byte16Image is virtual. 0 otherwise.

firstByte

pointer to the first short in this Byte16Image.

Constants

Return Codes

Return codes from various byte16 primitives. DVM_BYTE16_OK indicates the primitives executed successfully. DVM_BYTE16_ERROR indicates some error has occurs. We may defined more error codes to indicates different type of errors.

    #define DVM_BYTE16_OK 0
    #define DVM_BYTE16_ERROR 1

Operators

Allocation

Byte16Image *Byte16New (int w, int h)

Create a new physical Byte16Image with w x h shorts and return a pointer to that Byte16Image.

void Byte16Free (Byte16Image *image)

Deallocate image.

Byte16Image *Byte16Clip (Byte16Image *image, int x, int y, int w, int h)

Create a virtual Byte16Image of size w by h, with image as the parent, and offset (x, y) from the upper-left corner of image. A pointer to the new Byte16Image is returned.

void Byte16Reclip (Byte16Image *image, int x, int y, int w, int h, Byte16Image *clipped)

This function is identical to Byte16Clip, except that it destructively modifies the virtual Byte16Image clipped (instead of creating a new virtual Byte16Image). Warning : memory leaks will occurs if clipped is a physical Byte16Image.

Initialization

void Byte16Copy (Byte16Image *src, Byte16Image *dest)

Copy the top-left w x h area of Byte16Image src into Byte16Image dest, where w and h are minimum width and height of src and dest.

Queries

int Byte16GetX(Byte16Image *image) int Byte16GetY(Byte16Image *image) int Byte16GetWidth(Byte16Image *image) int Byte16GetHeight(Byte16Image *image) int Byte16GetVirtual(Byte16Image *image)

These functions (macros in the C version) access various fields in the Byte16Image data structure. The first two function return the x or y offset of image within its parent, the next two return the width or height of image, and the last function returns 1 if image is virtual, 0 otherwise.