From 5244b07d6aba16a775660f1a60456f5d76b1626d Mon Sep 17 00:00:00 2001
From: Liao Junxuan <mikeljx@126.com>
Date: Mon, 20 Nov 2023 19:20:51 +0800
Subject: [PATCH 1/2] Add support for zoom gesture

---
 zathura/callbacks.c | 25 +++++++++++++++++++++++++
 zathura/callbacks.h |  3 +++
 zathura/zathura.c   |  7 +++++++
 zathura/zathura.h   |  8 ++++++++
 4 files changed, 43 insertions(+)

diff --git a/zathura/callbacks.c b/zathura/callbacks.c
index 5c1c039..fd9b743 100644
--- a/zathura/callbacks.c
+++ b/zathura/callbacks.c
@@ -808,3 +808,28 @@ cb_window_update_icon(ZathuraRenderRequest* GIRARA_UNUSED(request), cairo_surfac
   gtk_window_set_icon(GTK_WINDOW(zathura->ui.session->gtk.window), pixbuf);
   g_object_unref(pixbuf);
 }
+
+void
+cb_gesture_zoom_begin(GtkGesture* UNUSED(self), GdkEventSequence* UNUSED(sequence), void* data)
+{
+  zathura_t* zathura = data;
+  if (zathura == NULL || zathura->document == NULL) {
+    return;
+  }
+  const double current_zoom     = zathura_document_get_zoom(zathura->document);
+  zathura->gesture.initial_zoom = current_zoom;
+}
+
+void
+cb_gesture_zoom_scale_changed(GtkGestureZoom* UNUSED(self), gdouble scale, void* data)
+{
+  zathura_t* zathura = data;
+  if (zathura == NULL || zathura->document == NULL) {
+    return;
+  }
+
+  const double next_zoom = zathura->gesture.initial_zoom * scale;
+  zathura_document_set_zoom(zathura->document, next_zoom);
+  render_all(zathura);
+  refresh_view(zathura);
+}
diff --git a/zathura/callbacks.h b/zathura/callbacks.h
index 8cbaaf8..c8520ee 100644
--- a/zathura/callbacks.h
+++ b/zathura/callbacks.h
@@ -281,5 +281,8 @@ void update_visible_pages(zathura_t* zathura);
  */
 void cb_window_update_icon(ZathuraRenderRequest* request, cairo_surface_t* surface, void* data);
 
+void cb_gesture_zoom_begin(GtkGesture* self, GdkEventSequence* sequence, void* data);
+
+void cb_gesture_zoom_scale_changed(GtkGestureZoom* self, gdouble scale, void* data);
 
 #endif // CALLBACKS_H
diff --git a/zathura/zathura.c b/zathura/zathura.c
index 033cb95..2370f0b 100644
--- a/zathura/zathura.c
+++ b/zathura/zathura.c
@@ -221,6 +221,13 @@ init_ui(zathura_t* zathura)
   zathura->ui.session->events.buffer_changed  = cb_buffer_changed;
   zathura->ui.session->events.unknown_command = cb_unknown_command;
 
+  /* gestures */
+
+  GtkGesture* zoom = gtk_gesture_zoom_new(GTK_WIDGET(zathura->ui.session->gtk.view));
+  g_signal_connect(zoom, "scale-changed", G_CALLBACK(cb_gesture_zoom_scale_changed), zathura);
+  g_signal_connect(zoom, "begin", G_CALLBACK(cb_gesture_zoom_begin), zathura);
+  gtk_event_controller_set_propagation_phase(GTK_EVENT_CONTROLLER(zathura->ui.session->gtk.view), GTK_PHASE_BUBBLE);
+
   /* zathura signals */
   zathura->signals.refresh_view = g_signal_new(
     "refresh-view", GTK_TYPE_WIDGET, G_SIGNAL_RUN_LAST, 0, NULL, NULL,
diff --git a/zathura/zathura.h b/zathura/zathura.h
index a9cf41e..55f44f2 100644
--- a/zathura/zathura.h
+++ b/zathura/zathura.h
@@ -226,6 +226,14 @@ struct zathura_s
     } toggle_presentation_mode;
   } shortcut;
 
+  /**
+   * Storage for gestures.
+   */
+  struct {
+	  double initial_zoom;
+  } gesture;
+
+
   /**
    * Context for MIME type detection
    */

From 1419beccd013be576303550746d841036837ee6c Mon Sep 17 00:00:00 2001
From: Liao Junxuan <mikeljx@126.com>
Date: Mon, 20 Nov 2023 21:23:16 +0800
Subject: [PATCH 2/2] Apply zoom limits to the zoom gesture

---
 zathura/callbacks.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/zathura/callbacks.c b/zathura/callbacks.c
index fd9b743..36bf2fd 100644
--- a/zathura/callbacks.c
+++ b/zathura/callbacks.c
@@ -829,7 +829,8 @@ cb_gesture_zoom_scale_changed(GtkGestureZoom* UNUSED(self), gdouble scale, void*
   }
 
   const double next_zoom = zathura->gesture.initial_zoom * scale;
-  zathura_document_set_zoom(zathura->document, next_zoom);
+  const double corrected_zoom = zathura_correct_zoom_value(zathura->ui.session, next_zoom);
+  zathura_document_set_zoom(zathura->document, corrected_zoom);
   render_all(zathura);
   refresh_view(zathura);
 }