Center zoomed area

Makefile

@@ -1,6 +1,6 @@
 all: sxiv
 
-VERSION=git-20110415
+VERSION=git-20110419
 
 CC?=gcc
 PREFIX?=/usr/local

image.c

@@ -212,8 +212,8 @@ int img_center(img_t *img, win_t *win) {
 	return ox != img->x || oy != img->y;
 }
 
-int img_zoom(img_t *img, float z) {
-	if (!img || !img->im)
+int img_zoom(img_t *img, win_t *win, float z) {
+	if (!img || !img->im || !win)
 		return 0;
 
 	z = MAX(z, zoom_min);
@@ -222,8 +222,8 @@ int img_zoom(img_t *img, float z) {
 	img->scalemode = SCALE_ZOOM;
 
 	if (z != img->zoom) {
-		img->x -= (img->w * z - img->w * img->zoom) / 2;
-		img->y -= (img->h * z - img->h * img->zoom) / 2;
+		img->x = win->w / 2 - (win->w / 2 - img->x) * z / img->zoom;
+		img->y = win->h / 2 - (win->h / 2 - img->y) * z / img->zoom;
 		img->zoom = z;
 		img->checkpan = 1;
 		return 1;
@@ -232,28 +232,28 @@ int img_zoom(img_t *img, float z) {
 	}
 }
 
-int img_zoom_in(img_t *img) {
+int img_zoom_in(img_t *img, win_t *win) {
 	int i;
 
-	if (!img || !img->im)
+	if (!img || !img->im || !win)
 		return 0;
 
 	for (i = 1; i < zl_cnt; ++i) {
 		if (zoom_levels[i] > img->zoom * 100.0)
-			return img_zoom(img, zoom_levels[i] / 100.0);
+			return img_zoom(img, win, zoom_levels[i] / 100.0);
 	}
 	return 0;
 }
 
-int img_zoom_out(img_t *img) {
+int img_zoom_out(img_t *img, win_t *win) {
 	int i;
 
-	if (!img || !img->im)
+	if (!img || !img->im || !win)
 		return 0;
 
 	for (i = zl_cnt - 2; i >= 0; --i) {
 		if (zoom_levels[i] < img->zoom * 100.0)
-			return img_zoom(img, zoom_levels[i] / 100.0);
+			return img_zoom(img, win, zoom_levels[i] / 100.0);
 	}
 	return 0;
 }

image.h

@@ -63,9 +63,9 @@ void img_render(img_t*, win_t*);
 int img_fit_win(img_t*, win_t*);
 int img_center(img_t*, win_t*);
 
-int img_zoom(img_t*, float);
-int img_zoom_in(img_t*);
-int img_zoom_out(img_t*);
+int img_zoom(img_t*, win_t*, float);
+int img_zoom_in(img_t*, win_t*);
+int img_zoom_out(img_t*, win_t*);
 
 int img_move(img_t*, win_t*, int, int);
 int img_pan(img_t*, win_t*, pandir_t);

main.c

@@ -424,13 +424,13 @@ void on_keypress(XKeyEvent *kev) {
 			/* zooming */
 			case XK_plus:
 			case XK_equal:
-				changed = img_zoom_in(&img);
+				changed = img_zoom_in(&img, &win);
 				break;
 			case XK_minus:
-				changed = img_zoom_out(&img);
+				changed = img_zoom_out(&img, &win);
 				break;
 			case XK_0:
-				changed = img_zoom(&img, 1.0);
+				changed = img_zoom(&img, &win, 1.0);
 				break;
 			case XK_w:
 				if ((changed = img_fit_win(&img, &win)))
@@ -607,7 +607,7 @@ void on_buttonpress(XButtonEvent *bev) {
 				break;
 			case Button4:
 				if (mask == ControlMask)
-					changed = img_zoom_in(&img);
+					changed = img_zoom_in(&img, &win);
 				else if (mask == ShiftMask)
 					changed = img_pan(&img, &win, PAN_LEFT);
 				else
@@ -615,7 +615,7 @@ void on_buttonpress(XButtonEvent *bev) {
 				break;
 			case Button5:
 				if (mask == ControlMask)
-					changed = img_zoom_out(&img);
+					changed = img_zoom_out(&img, &win);
 				else if (mask == ShiftMask)
 					changed = img_pan(&img, &win, PAN_RIGHT);
 				else