[PATCH weston 3/4 v2] Center zoom area for text cursor position.

[Scott Moreau]

Here we install the logic for 'zoom area centered on a given point'.
---

Rebased against master, 380deee3c7b18574d66511287bb01dde51027fbf

 src/compositor.c |   29 ++++++++++++++++++++++-------
 src/compositor.h |    2 +-
 src/shell.c      |    2 +-
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/compositor.c b/src/compositor.c
index 75bda93..20874c6 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -1625,7 +1625,7 @@ notify_motion(struct wl_seat *seat, uint32_t time, wl_fixed_t x, wl_fixed_t y)
 		if (output->zoom.active &&
 		    pixman_region32_contains_point(&output->region,
 						   ix, iy, NULL))
-			weston_output_update_zoom(output, x, y);
+			weston_output_update_zoom(output, x, y, 0);
 
 	weston_device_repick(seat);
 	interface = seat->pointer->grab->interface;
@@ -2456,13 +2456,14 @@ weston_text_cursor_position_notify(struct weston_surface *surface,
 		if (output->zoom.active &&
 		    pixman_region32_contains_point(&output->region,
 							cur_pos_x, cur_pos_y, NULL))
-			weston_output_update_zoom(output, cur_pos_x * 256, cur_pos_y * 256);
+			weston_output_update_zoom(output, cur_pos_x * 256, cur_pos_y * 256, 1);
 }
 
 WL_EXPORT void
-weston_output_update_zoom(struct weston_output *output, wl_fixed_t fx, wl_fixed_t fy)
+weston_output_update_zoom(struct weston_output *output, wl_fixed_t fx, wl_fixed_t fy, int text_cursor)
 {
 	int32_t x, y;
+	float trans_min, trans_max;
 
 	if (output->zoom.level >= 1.0)
 		return;
@@ -2470,10 +2471,24 @@ weston_output_update_zoom(struct weston_output *output, wl_fixed_t fx, wl_fixed_
 	x = wl_fixed_to_int(fx);
 	y = wl_fixed_to_int(fy);
 
-	output->zoom.trans_x = (((float)(x - output->x) / output->current->width) *
-					(output->zoom.level * 2)) - output->zoom.level;
-	output->zoom.trans_y = (((float)(y - output->y) / output->current->height) *
-					(output->zoom.level * 2)) - output->zoom.level;
+	trans_max = output->zoom.level * 2 - output->zoom.level;
+	trans_min = -trans_max;
+
+	output->zoom.trans_x = ((((float)(x - output->x) / output->current->width) *
+					(output->zoom.level * 2)) - output->zoom.level) *
+					(text_cursor ? (1 / output->zoom.level) : 1);
+	output->zoom.trans_y = ((((float)(y - output->y) / output->current->height) *
+					(output->zoom.level * 2)) - output->zoom.level) *
+					(text_cursor ? (1 / output->zoom.level) : 1);
+
+	if (output->zoom.trans_x > trans_max)
+		output->zoom.trans_x = trans_max;
+	else if (output->zoom.trans_x < trans_min)
+		output->zoom.trans_x = trans_min;
+	if (output->zoom.trans_y > trans_max)
+		output->zoom.trans_y = trans_max;
+	else if (output->zoom.trans_y < trans_min)
+		output->zoom.trans_y = trans_min;
 
 	output->dirty = 1;
 	weston_output_damage(output);
diff --git a/src/compositor.h b/src/compositor.h
index 1b3d08c..7a84082 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -551,7 +551,7 @@ weston_compositor_init(struct weston_compositor *ec, struct wl_display *display)
 void
 weston_compositor_shutdown(struct weston_compositor *ec);
 void
-weston_output_update_zoom(struct weston_output *output, int x, int y);
+weston_output_update_zoom(struct weston_output *output, int x, int y, int text_cursor);
 void
 weston_text_cursor_position_notify(struct weston_surface *surface, int x, int y);
 void
diff --git a/src/shell.c b/src/shell.c
index 6c9ee93..c2581f1 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -1659,7 +1659,7 @@ zoom_binding(struct wl_seat *seat, uint32_t time,
 
 			weston_output_update_zoom(output,
 			                          seat->pointer->x,
-						  seat->pointer->y);
+						  seat->pointer->y, 0);
 		}
 	}
 }
-- 
1.7.7.6