[PATCH] games/blit: render screen from top to bottom rather than around center

[Tony Kaku <tonykaku@openmailbox.org>]

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It makes more sense to favor showing the top of the screen than the
middle when the enclosing window's dimensions are smaller than
800x1024.

The cursors' alignment is still kinda wonky, but you can make them
align by moving the host cursor outside the window and moving it back
in through the top left corner.

Also added -m flag for easier keeping track of cursor alignment.

tkk


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diff -r f1b3bbf7c96b sys/src/games/blit/blit.c
--- a/sys/src/games/blit/blit.c	Tue Apr 11 02:26:39 2017 +0200
+++ b/sys/src/games/blit/blit.c	Fri Apr 14 15:57:12 2017 +0200
@@ -10,7 +10,6 @@
 
 int baud = 40000;
 int scale = 1;
-Rectangle picr;
 Image *tmp, *bg;
 Channel *keych, *uartrxch, *uarttxch;
 Mousectl *mc;
@@ -26,10 +25,6 @@
 static void
 screeninit(void)
 {
-	Point p;
-
-	p = divpt(addpt(screen->r.min, screen->r.max), 2);
-	picr = (Rectangle){subpt(p, Pt(scale * SX/2, scale * SY/2)), addpt(p, Pt(scale * SX/2, scale * SY/2))};
 	if(tmp != nil) freeimage(tmp);
 	tmp = allocimage(display, Rect(0, 0, scale * SX, scale > 1 ? 1 : scale * SY), CHAN1(CMap, 1), scale > 1, 0);
 	if(bg != nil) freeimage(bg);
@@ -56,9 +51,9 @@
 		screeninit();
 	}
 	while(nbrecv(mc->c, &m) > 0){
-		if(ptinrect(m.xy, picr)){
-			mousex = picr.max.x - m.xy.x - 1;
-			mousey = picr.max.y - m.xy.y - 1;
+		if(ptinrect(m.xy, screen->r)){
+			mousex = screen->r.max.x - m.xy.x - 1;
+			mousey = screen->r.max.y - m.xy.y - 1;
 		}
 		n = m.buttons >> 2 & 1 | m.buttons & 2 | m.buttons << 2 & 4;
 		if(n != mousebut){
@@ -88,10 +83,10 @@
 
 	loadimage(tmp, r, pic+o, Dy(r)*(SX/8));
 	if(realcolors){
-		draw(screen, rectaddpt(r, picr.min), colfg, nil, r.min);
-		draw(screen, rectaddpt(r, picr.min), colbg, tmp, r.min);
+		draw(screen, rectaddpt(r, screen->r.min), colfg, nil, r.min);
+		draw(screen, rectaddpt(r, screen->r.min), colbg, tmp, r.min);
 	}else
-		draw(screen, rectaddpt(r, picr.min), tmp, nil, r.min);
+		draw(screen, rectaddpt(r, screen->r.min), tmp, nil, r.min);
 	updated = Rect(SX, SY, 0, 0);
 	flushimage(display, 1);
 }
@@ -157,12 +152,13 @@
 void
 threadmain(int argc, char **argv)
 {
-	int n;
+	int n, ms;
 	static Cursor blank;
 	char *telnet;
 	char *p;
 	extern int diag;
 	
+	ms = 0;
 	telnet = nil;
 	ARGBEGIN{
 	case 'b':
@@ -184,6 +180,9 @@
 	case 'd':
 		diag++;
 		break;
+	case 'm':
+		ms++;
+		break;
 	default: usage();
 	}ARGEND;
 	if(argc != 0) usage();
@@ -201,7 +200,8 @@
 	mc = initmouse(nil, screen);
 	if(mc == nil)
 		sysfatal("initmouse: %r");
-	setcursor(mc, &blank);
+	if(ms == 0)
+		setcursor(mc, &blank);
 
 	cpureset();
 	for(;;){