Mouse drag translates pointer position to image area

This makes mouse panning more direct and faster.

Makefile

@@ -1,4 +1,4 @@
-VERSION := git-20170908
+VERSION := git-20171004
 
 all: sxiv
 

commands.c

@@ -320,72 +320,41 @@ bool ci_scroll_to_edge(arg_t dir)
 	return img_pan_edge(&img, dir);
 }
 
-/* Xlib helper function for i_drag() */
-Bool is_motionnotify(Display *d, XEvent *e, XPointer a)
-{
-	return e != NULL && e->type == MotionNotify;
-}
-
-#define WARP(x,y) \
-	XWarpPointer(win.env.dpy, None, win.xwin, 0, 0, 0, 0, x, y); \
-	ox = x, oy = y; \
-	break
-
 bool ci_drag(arg_t _)
 {
-	int dx = 0, dy = 0, i, ox, oy, x, y;
+	int i, x, y;
+	float px, py;
 	unsigned int ui;
-	bool dragging = true, next = false;
 	XEvent e;
 	Window w;
 
-	if (!XQueryPointer(win.env.dpy, win.xwin, &w, &w, &i, &i, &ox, &oy, &ui))
+	if ((int)(img.w * img.zoom) < win.w && (int)(img.h * img.zoom) < win.h)
+		return false;
+	if (!XQueryPointer(win.env.dpy, win.xwin, &w, &w, &i, &i, &x, &y, &ui))
 		return false;
 	
-	win_set_cursor(&win, CURSOR_HAND);
+	win_set_cursor(&win, CURSOR_DRAG);
 
-	while (dragging) {
-		if (!next)
-			XMaskEvent(win.env.dpy,
-			           ButtonPressMask | ButtonReleaseMask | PointerMotionMask, &e);
-		switch (e.type) {
-			case ButtonPress:
-			case ButtonRelease:
-				dragging = false;
-				break;
-			case MotionNotify:
-				x = e.xmotion.x;
-				y = e.xmotion.y;
+	for (;;) {
+		px = MIN(MAX(0.0, x - win.w*0.1), win.w*0.8) / (win.w*0.8)
+		   * (win.w - img.w * img.zoom);
+		py = MIN(MAX(0.0, y - win.h*0.1), win.h*0.8) / (win.h*0.8)
+		   * (win.h - img.h * img.zoom);
 
-				/* wrap the mouse around */
-				if (x <= 0) {
-					WARP(win.w - 2, y);
-				} else if (x >= win.w - 1) {
-					WARP(1, y);
-				} else if (y <= 0) {
-					WARP(x, win.h - 2);
-				} else if (y >= win.h - 1) {
-					WARP(x, 1);
-				}
-				dx += x - ox;
-				dy += y - oy;
-				ox = x;
-				oy = y;
-				break;
-		}
-		if (dragging)
-			next = XCheckIfEvent(win.env.dpy, &e, is_motionnotify, None);
-		if ((!dragging || !next) && (dx != 0 || dy != 0)) {
-			if (img_move(&img, dx, dy)) {
+		if (img_pos(&img, px, py)) {
 			img_render(&img);
 			win_draw(&win);
 		}
-			dx = dy = 0;
-		}
+		XMaskEvent(win.env.dpy,
+		           ButtonPressMask | ButtonReleaseMask | PointerMotionMask, &e);
+		if (e.type == ButtonPress || e.type == ButtonRelease)
+			break;
+		while (XCheckTypedEvent(win.env.dpy, MotionNotify, &e));
+		x = e.xmotion.x;
+		y = e.xmotion.y;
 	}
 	win_set_cursor(&win, CURSOR_ARROW);
 	set_timeout(reset_cursor, TO_CURSOR_HIDE, true);
-	reset_timeout(redraw);
 
 	return true;
 }

image.c

@@ -567,15 +567,15 @@ bool img_zoom_out(img_t *img)
 	return false;
 }
 
-bool img_move(img_t *img, float dx, float dy)
+bool img_pos(img_t *img, float x, float y)
 {
 	float ox, oy;
 
 	ox = img->x;
 	oy = img->y;
 
-	img->x += dx;
-	img->y += dy;
+	img->x = x;
+	img->y = y;
 
 	img_check_pan(img, true);
 
@@ -587,6 +587,11 @@ bool img_move(img_t *img, float dx, float dy)
 	}
 }
 
+bool img_move(img_t *img, float dx, float dy)
+{
+	return img_pos(img, img->x + dx, img->y + dy);
+}
+
 bool img_pan(img_t *img, direction_t dir, int d)
 {
 	/* d < 0: screen-wise

image.h

@@ -80,6 +80,7 @@ bool img_zoom(img_t*, float);
 bool img_zoom_in(img_t*);
 bool img_zoom_out(img_t*);
 
+bool img_pos(img_t*, float, float);
 bool img_move(img_t*, float, float);
 bool img_pan(img_t*, direction_t, int);
 bool img_pan_edge(img_t*, direction_t);

main.c

@@ -741,6 +741,7 @@ void run(void)
 				XPeekEvent(win.env.dpy, &nextev);
 				switch (ev.type) {
 					case ConfigureNotify:
+					case MotionNotify:
 						discard = ev.type == nextev.type;
 						break;
 					case KeyPress:

types.h

@@ -66,7 +66,7 @@ typedef enum {
 typedef enum {
 	CURSOR_ARROW,
 	CURSOR_NONE,
-	CURSOR_HAND,
+	CURSOR_DRAG,
 	CURSOR_WATCH
 } cursor_t;
 

window.c

@@ -37,7 +37,7 @@ enum {
 
 static Cursor carrow;
 static Cursor cnone;
-static Cursor chand;
+static Cursor cdrag;
 static Cursor cwatch;
 static GC gc;
 
@@ -210,7 +210,7 @@ void win_open(win_t *win)
 	             PointerMotionMask | StructureNotifyMask);
 
 	carrow = XCreateFontCursor(e->dpy, XC_left_ptr);
-	chand = XCreateFontCursor(e->dpy, XC_fleur);
+	cdrag = XCreateFontCursor(e->dpy, XC_dotbox);
 	cwatch = XCreateFontCursor(e->dpy, XC_watch);
 
 	if (XAllocNamedColor(e->dpy, DefaultColormap(e->dpy, e->scr), "black",
@@ -277,7 +277,7 @@ CLEANUP void win_close(win_t *win)
 {
 	XFreeCursor(win->env.dpy, carrow);
 	XFreeCursor(win->env.dpy, cnone);
-	XFreeCursor(win->env.dpy, chand);
+	XFreeCursor(win->env.dpy, cdrag);
 	XFreeCursor(win->env.dpy, cwatch);
 
 	XFreeGC(win->env.dpy, gc);
@@ -465,8 +465,8 @@ void win_set_cursor(win_t *win, cursor_t cursor)
 		case CURSOR_NONE:
 			XDefineCursor(win->env.dpy, win->xwin, cnone);
 			break;
-		case CURSOR_HAND:
-			XDefineCursor(win->env.dpy, win->xwin, chand);
+		case CURSOR_DRAG:
+			XDefineCursor(win->env.dpy, win->xwin, cdrag);
 			break;
 		case CURSOR_WATCH:
 			XDefineCursor(win->env.dpy, win->xwin, cwatch);