Writing bitmaps to files

Bitmaps can be written to files by sending the writeBitmapFile:width:height:xHot:yHot: message to the bitmap.

Tip:

The bitmap file format only supports a CgPixmap of depth one. It is an error to try to write a CgPixmap with a different depth.

The bitmap is written in X11 bitmap file format, which looks like C source code for a structure initialization. Parameters passed to the method include the file name, the width, the height, and the hot spot coordinates within the bitmap. A hot spot is useful for cursor specifications. The write operation returns zero if successful, or an error value if unsuccessful.

| bits bitmap error |

bits := #

2r11111111 2r00000001 2r00000001 2r00000001

2r11111111 2r00010000 2r00010000 2r00010000].

bitmap := CgWindow default

createBitmapFromData: bits

width: 8

height: 8.

error := bitmap

writeBitmapFile: 'brick'

width: 8

height: 8

xHot: 0

yHot: 0.

error = 0

ifTrue: [Transcript cr; show: 'File write successful.']

ifFalse: [Transcript cr; show: 'File write error: ',

error printString].

bitmap freePixmap.

The file created by this example follows:

#define brick_width 8

#define brick_height 8

#define brick_x_hot 0

#define brick_y_hot 0

static char brick_bits] = {

0xff, 0x01, 0x01, 0x01, 0xff, 0x10, 0x10, 0x10};