From 8f98c623ee5601ab10607d0da9a1801351a66d45 Mon Sep 17 00:00:00 2001
From: Přemysl Eric Janouch <p@janouch.name>
Date: Sun, 17 Jul 2022 08:50:11 +0200
Subject: Center zoom around pointer or middle of the view
---
fiv-view.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 53 insertions(+), 16 deletions(-)
diff --git a/fiv-view.c b/fiv-view.c
index 1fa4880..b16dee1 100644
--- a/fiv-view.c
+++ b/fiv-view.c
@@ -543,9 +543,9 @@ fiv_view_draw(GtkWidget *widget, cairo_t *cr)
double x = 0;
double y = 0;
if (self->hadjustment)
- x = -gtk_adjustment_get_value(self->hadjustment);
+ x = -floor(gtk_adjustment_get_value(self->hadjustment));
if (self->vadjustment)
- y = -gtk_adjustment_get_value(self->vadjustment);
+ y = -floor(gtk_adjustment_get_value(self->vadjustment));
if (w < allocation.width)
x = round((allocation.width - w) / 2.);
if (h < allocation.height)
@@ -645,15 +645,52 @@ set_scale_to_fit(FivView *self, bool scale_to_fit)
}
static gboolean
-set_scale(FivView *self, double scale)
+set_scale(FivView *self, double scale, const GdkEvent *event)
{
- if (self->scale != scale) {
- self->scale = scale;
- g_object_notify_by_pspec(G_OBJECT(self), view_properties[PROP_SCALE]);
- prescale_page(self);
+ if (self->scale == scale)
+ goto out;
- gtk_widget_queue_resize(GTK_WIDGET(self));
+ GtkAllocation allocation;
+ gtk_widget_get_allocation(GTK_WIDGET(self), &allocation);
+
+ double focus_x = 0, focus_y = 0, surface_x = 0, surface_y = 0;
+ if (!event || !gdk_event_get_coords(event, &focus_x, &focus_y)) {
+ focus_x = 0.5 * allocation.width;
+ focus_y = 0.5 * allocation.height;
+ }
+ if (self->hadjustment && self->vadjustment) {
+ int w, h;
+ get_display_dimensions(self, &w, &h);
+
+ surface_x = (focus_x + (w < allocation.width
+ ? -round((allocation.width - w) / 2.)
+ : +floor(gtk_adjustment_get_value(self->hadjustment))))
+ / self->scale;
+ surface_y = (focus_y + (h < allocation.height
+ ? -round((allocation.height - h) / 2.)
+ : +floor(gtk_adjustment_get_value(self->vadjustment))))
+ / self->scale;
+ }
+
+ self->scale = scale;
+ g_object_notify_by_pspec(G_OBJECT(self), view_properties[PROP_SCALE]);
+ prescale_page(self);
+
+ if (self->hadjustment && self->vadjustment) {
+ update_adjustments(self);
+
+ Dimensions surface_dimensions = get_surface_dimensions(self);
+ if (surface_dimensions.width * self->scale > allocation.width)
+ gtk_adjustment_set_value(
+ self->hadjustment, surface_x * self->scale - focus_x);
+ if (surface_dimensions.height * self->scale > allocation.height)
+ gtk_adjustment_set_value(
+ self->vadjustment, surface_y * self->scale - focus_y);
}
+
+ gtk_widget_queue_resize(GTK_WIDGET(self));
+
+out:
return set_scale_to_fit(self, false);
}
@@ -663,7 +700,7 @@ set_scale_to_fit_width(FivView *self)
double w = get_surface_dimensions(self).width;
int allocated = gtk_widget_get_allocated_width(GTK_WIDGET(self));
if (ceil(w * self->scale) > allocated)
- set_scale(self, allocated / w);
+ set_scale(self, allocated / w, NULL);
}
static void
@@ -672,7 +709,7 @@ set_scale_to_fit_height(FivView *self)
double h = get_surface_dimensions(self).height;
int allocated = gtk_widget_get_allocated_height(GTK_WIDGET(self));
if (ceil(h * self->scale) > allocated)
- set_scale(self, allocated / h);
+ set_scale(self, allocated / h, NULL);
}
static gboolean
@@ -686,9 +723,9 @@ fiv_view_scroll_event(GtkWidget *widget, GdkEventScroll *event)
switch (event->direction) {
case GDK_SCROLL_UP:
- return set_scale(self, self->scale * SCALE_STEP);
+ return set_scale(self, self->scale * SCALE_STEP, (GdkEvent *) event);
case GDK_SCROLL_DOWN:
- return set_scale(self, self->scale / SCALE_STEP);
+ return set_scale(self, self->scale / SCALE_STEP, (GdkEvent *) event);
default:
// For some reason, native GdkWindows may also get GDK_SCROLL_SMOOTH.
// Left/right are good to steal from GtkScrolledWindow for consistency.
@@ -1196,7 +1233,7 @@ fiv_view_key_press_event(GtkWidget *widget, GdkEventKey *event)
if (self->image &&
!(event->state & gtk_accelerator_get_default_mod_mask()) &&
event->keyval >= GDK_KEY_1 && event->keyval <= GDK_KEY_9)
- return set_scale(self, event->keyval - GDK_KEY_0);
+ return set_scale(self, event->keyval - GDK_KEY_0, NULL);
return GTK_WIDGET_CLASS(fiv_view_parent_class)
->key_press_event(widget, event);
@@ -1538,11 +1575,11 @@ fiv_view_command(FivView *self, FivViewCommand command)
info(self);
break; case FIV_VIEW_COMMAND_ZOOM_IN:
- set_scale(self, self->scale * SCALE_STEP);
+ set_scale(self, self->scale * SCALE_STEP, NULL);
break; case FIV_VIEW_COMMAND_ZOOM_OUT:
- set_scale(self, self->scale / SCALE_STEP);
+ set_scale(self, self->scale / SCALE_STEP, NULL);
break; case FIV_VIEW_COMMAND_ZOOM_1:
- set_scale(self, 1.0);
+ set_scale(self, 1.0, NULL);
break; case FIV_VIEW_COMMAND_FIT_WIDTH:
set_scale_to_fit_width(self);
break; case FIV_VIEW_COMMAND_FIT_HEIGHT:
--
cgit v1.2.3-70-g09d2