-- JaMSnapImpl.mesa
-- Last changed by Doug Wyatt, January 16, 1981  12:13 PM

DIRECTORY
	AltoDevice USING [Bitmap, ScreenBitmap],
	Blt USING [Handle, New, Source, SetBox, Rect],
	JaMFnsDefs USING [Register, PopString],
	JaMGraphicsDefs USING [GetDC],
	JaMSnapDefs USING [],
	PressDefs USING [PressFileDescriptor, InitPressFileDescriptor,
		PutComputedDots, ClosePressFile];

JaMSnapImpl: PROGRAM
IMPORTS AltoDevice, Blt, JaMFnsDefs, JaMGraphicsDefs, PressDefs
EXPORTS JaMSnapDefs = {

pfd: PressDefs.PressFileDescriptor;

linew: CARDINAL = 40;
line: ARRAY[0..linew) OF WORD;
bb: Blt.Handle _ Blt.New[@line,linew];

JSnap: PROCEDURE = {
	bm: AltoDevice.Bitmap _ AltoDevice.ScreenBitmap[];
	w: CARDINAL _ 16*bm.raster;
	h: CARDINAL _ bm.height;
	y: CARDINAL_0;
	NextScanLine: PROCEDURE RETURNS[POINTER] = {
		Blt.Rect[bb];
		bb.sdy_bb.sdy-1;
		RETURN[@line];
		};
	filename: STRING _ [100];
	JaMFnsDefs.PopString[filename];
	Blt.Source[bb,bm.base,bm.raster];
	bb.bbt.sourcetype _ block;
	Blt.SetBox[bb,0,0,w,1];
	PressDefs.InitPressFileDescriptor[@pfd,filename];
	PressDefs.PutComputedDots[p: @pfd, x: 1270, y: 26670-32*h,
		nPixels: w, nScanLines: h, bitsPerPixel: 0,
		width: 32*w, height: 32*h, nextScanLine: NextScanLine];
	PressDefs.ClosePressFile[@pfd];
	};

[]_JaMGraphicsDefs.GetDC[]; -- to make sure it's started
JaMFnsDefs.Register[".snap",JSnap];

}.(670)