Add ability to keep zoom/position when browsing

6 files changed, 189 insertions, 4 deletions

diff --git a/README.adoc b/README.adoc
index d245a0f..965cb62 100644
--- a/README.adoc
+++ b/README.adoc
@@ -14,6 +14,8 @@ Features
  - Employs high-performance file format libraries: Wuffs and libjpeg-turbo.
  - Makes use of 30-bit X.org visuals, whenever it's possible and appropriate.
  - Has a notion of pages, and tries to load all included content within files.
+ - Can keep the zoom and position when browsing, to help with comparing
+   zoomed-in images.
 
 Explicit non-goals
 ------------------
diff --git a/fiv-view.c b/fiv-view.c
index 01bedc8..8a42d04 100644
--- a/fiv-view.c
+++ b/fiv-view.c
@@ -67,6 +67,7 @@ struct _FivView {
 	bool checkerboard : 1;              ///< Show checkerboard background
 	bool enhance : 1;                   ///< Try to enhance picture data
 	bool scale_to_fit : 1;              ///< Image no larger than the allocation
+	bool fixate : 1;                    ///< Keep zoom and position
 	double scale;                       ///< Scaling factor
 	double drag_start[2];               ///< Adjustment values for drag origin
 
@@ -125,6 +126,7 @@ enum {
 	PROP_MESSAGES = 1,
 	PROP_SCALE,
 	PROP_SCALE_TO_FIT,
+	PROP_FIXATE,
 	PROP_ENABLE_CMS,
 	PROP_FILTER,
 	PROP_CHECKERBOARD,
@@ -254,6 +256,9 @@ fiv_view_get_property(
 	case PROP_SCALE_TO_FIT:
 		g_value_set_boolean(value, self->scale_to_fit);
 		break;
+	case PROP_FIXATE:
+		g_value_set_boolean(value, self->fixate);
+		break;
 	case PROP_ENABLE_CMS:
 		g_value_set_boolean(value, self->enable_cms);
 		break;
@@ -311,6 +316,10 @@ fiv_view_set_property(
 		if (self->scale_to_fit != g_value_get_boolean(value))
 			fiv_view_command(self, FIV_VIEW_COMMAND_TOGGLE_SCALE_TO_FIT);
 		break;
+	case PROP_FIXATE:
+		if (self->fixate != g_value_get_boolean(value))
+			fiv_view_command(self, FIV_VIEW_COMMAND_TOGGLE_FIXATE);
+		break;
 	case PROP_ENABLE_CMS:
 		if (self->enable_cms != g_value_get_boolean(value))
 			fiv_view_command(self, FIV_VIEW_COMMAND_TOGGLE_CMS);
@@ -636,7 +645,12 @@ static gboolean
 set_scale_to_fit(FivView *self, bool scale_to_fit)
 {
 	if (self->scale_to_fit != scale_to_fit) {
-		self->scale_to_fit = scale_to_fit;
+		if ((self->scale_to_fit = scale_to_fit)) {
+			self->fixate = false;
+			g_object_notify_by_pspec(
+				G_OBJECT(self), view_properties[PROP_FIXATE]);
+		}
+
 		g_object_notify_by_pspec(
 			G_OBJECT(self), view_properties[PROP_SCALE_TO_FIT]);
 		gtk_widget_queue_resize(GTK_WIDGET(self));
@@ -1270,6 +1284,9 @@ fiv_view_class_init(FivViewClass *klass)
 	view_properties[PROP_SCALE_TO_FIT] = g_param_spec_boolean(
 		"scale-to-fit", "Scale to fit", "Scale images down to fit the window",
 		TRUE, G_PARAM_READWRITE);
+	view_properties[PROP_FIXATE] = g_param_spec_boolean(
+		"fixate", "Fixate", "Keep zoom and position",
+		FALSE, G_PARAM_READWRITE);
 	view_properties[PROP_ENABLE_CMS] = g_param_spec_boolean(
 		"enable-cms", "Enable CMS", "Enable color management",
 		TRUE, G_PARAM_READWRITE);
@@ -1443,7 +1460,10 @@ fiv_view_set_uri(FivView *self, const char *uri)
 	self->frame = self->page = NULL;
 	self->image = surface;
 	switch_page(self, self->image);
-	set_scale_to_fit(self, true);
+
+	// Otherwise, adjustment values and zoom are retained implicitly.
+	if (!self->fixate)
+		set_scale_to_fit(self, true);
 
 	g_free(self->uri);
 	self->uri = g_strdup(uri);
@@ -1592,5 +1612,10 @@ fiv_view_command(FivView *self, FivViewCommand command)
 		set_scale_to_fit_height(self);
 	break; case FIV_VIEW_COMMAND_TOGGLE_SCALE_TO_FIT:
 		set_scale_to_fit(self, !self->scale_to_fit);
+	break; case FIV_VIEW_COMMAND_TOGGLE_FIXATE:
+		if ((self->fixate = !self->fixate))
+			set_scale_to_fit(self, false);
+		g_object_notify_by_pspec(
+			G_OBJECT(self), view_properties[PROP_FIXATE]);
 	}
 }
diff --git a/fiv-view.h b/fiv-view.h
index c2d8b8b..7f4e3a3 100644
--- a/fiv-view.h
+++ b/fiv-view.h
@@ -60,7 +60,8 @@ typedef enum _FivViewCommand {
 	XX(FIV_VIEW_COMMAND_ZOOM_1,              "zoom-1")                         \
 	XX(FIV_VIEW_COMMAND_FIT_WIDTH,           "fit-width")                      \
 	XX(FIV_VIEW_COMMAND_FIT_HEIGHT,          "fit-height")                     \
-	XX(FIV_VIEW_COMMAND_TOGGLE_SCALE_TO_FIT, "toggle-scale-to-fit")
+	XX(FIV_VIEW_COMMAND_TOGGLE_SCALE_TO_FIT, "toggle-scale-to-fit")            \
+	XX(FIV_VIEW_COMMAND_TOGGLE_FIXATE,       "toggle-fixate")
 #define XX(constant, name) constant,
 	FIV_VIEW_COMMANDS(XX)
 #undef XX
diff --git a/fiv.c b/fiv.c
index dccc85f..73a996b 100644
--- a/fiv.c
+++ b/fiv.c
@@ -497,13 +497,13 @@ show_about_dialog(GtkWidget *parent)
 	XX(PLAY_PAUSE,    B("media-playback-start-symbolic", "Pause")) \
 	XX(SEEK_FORWARD,  B("media-seek-forward-symbolic", "Next frame")) \
 	XX(S3,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
+	XX(FIXATE,        T("pin2-symbolic", "Keep zoom and position")) \
 	XX(MINUS,         B("zoom-out-symbolic", "Zoom out")) \
 	XX(SCALE,         gtk_label_new("")) \
 	XX(PLUS,          B("zoom-in-symbolic", "Zoom in")) \
 	XX(ONE,           B("zoom-original-symbolic", "Original size")) \
 	XX(FIT,           T("zoom-fit-best-symbolic", "Scale to fit")) \
 	XX(S4,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
-	/* XX(PIN,        B("view-pin-symbolic", "Keep view configuration")) */ \
 	/* Or perhaps "blur-symbolic", also in the extended set. */ \
 	XX(COLOR,         T("preferences-color-symbolic", "Color management")) \
 	XX(SMOOTH,        T("blend-tool-symbolic", "Smooth scaling")) \
@@ -1523,6 +1523,7 @@ make_view_toolbar(void)
 	toolbar_command(TOOLBAR_PLUS,          FIV_VIEW_COMMAND_ZOOM_IN);
 	toolbar_command(TOOLBAR_ONE,           FIV_VIEW_COMMAND_ZOOM_1);
 	toolbar_toggler(TOOLBAR_FIT,           "scale-to-fit");
+	toolbar_toggler(TOOLBAR_FIXATE,        "fixate");
 	toolbar_toggler(TOOLBAR_COLOR,         "enable-cms");
 	toolbar_toggler(TOOLBAR_SMOOTH,        "filter");
 	toolbar_toggler(TOOLBAR_CHECKERBOARD,  "checkerboard");
@@ -1541,6 +1542,8 @@ make_view_toolbar(void)
 		G_CALLBACK(on_notify_view_playing), NULL);
 	g_signal_connect(g.view, "notify::scale-to-fit",
 		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_FIT]);
+	g_signal_connect(g.view, "notify::fixate",
+		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_FIXATE]);
 	g_signal_connect(g.view, "notify::enable-cms",
 		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_COLOR]);
 	g_signal_connect(g.view, "notify::filter",
@@ -1553,6 +1556,7 @@ make_view_toolbar(void)
 	g_object_notify(G_OBJECT(g.view), "scale");
 	g_object_notify(G_OBJECT(g.view), "playing");
 	g_object_notify(G_OBJECT(g.view), "scale-to-fit");
+	g_object_notify(G_OBJECT(g.view), "fixate");
 	g_object_notify(G_OBJECT(g.view), "enable-cms");
 	g_object_notify(G_OBJECT(g.view), "filter");
 	g_object_notify(G_OBJECT(g.view), "checkerboard");
diff --git a/resources/pin2-symbolic.svg b/resources/pin2-symbolic.svg
new file mode 100644
index 0000000..5b5fdab
--- /dev/null
+++ b/resources/pin2-symbolic.svg
@@ -0,0 +1,152 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg height="16px" viewBox="0 0 16 16" width="16px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+    <filter id="a" height="100%" width="100%" x="0%" y="0%">
+        <feColorMatrix in="SourceGraphic" type="matrix" values="0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 1 0"/>
+    </filter>
+    <mask id="b">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.3"/>
+        </g>
+    </mask>
+    <clipPath id="c">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="d">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="e">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="f">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="g">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="h">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="i">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="j">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="k">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="l">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="m">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="n">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.05"/>
+        </g>
+    </mask>
+    <clipPath id="o">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="p">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.3"/>
+        </g>
+    </mask>
+    <clipPath id="q">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="r">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.5"/>
+        </g>
+    </mask>
+    <clipPath id="s">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="t">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.4"/>
+        </g>
+    </mask>
+    <clipPath id="u">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="v">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.4"/>
+        </g>
+    </mask>
+    <clipPath id="w">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="x">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.5"/>
+        </g>
+    </mask>
+    <clipPath id="y">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <mask id="z">
+        <g filter="url(#a)">
+            <path d="m 0 0 h 16 v 16 h -16 z" fill-opacity="0.5"/>
+        </g>
+    </mask>
+    <clipPath id="A">
+        <path d="m 0 0 h 1024 v 800 h -1024 z"/>
+    </clipPath>
+    <path d="m 14 28 c 0 3.3125 -2.6875 6 -6 6 s -6 -2.6875 -6 -6 s 2.6875 -6 6 -6 s 6 2.6875 6 6 z m 0 0" fill="none" stroke="#2e3436" stroke-linecap="round" stroke-width="2"/>
+    <path d="m 6.992188 2 l -5.070313 4.992188 l 3.261719 2.539062 c -0.519532 2.046875 0.078125 4.214844 1.566406 5.710938 l 3.742188 -3.742188 l 4.5 4.5 h 1 v -1 l -4.5 -4.5 l 3.746093 -3.742188 c -1.5 -1.496093 -3.679687 -2.089843 -5.730469 -1.5625 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    <path d="m 1.992188 7 l 5 -5" fill="none" stroke="#2e3436" stroke-linecap="square" stroke-width="2"/>
+    <g clip-path="url(#c)" mask="url(#b)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 562.460938 212.058594 h 10.449218 c -1.183594 0.492187 -1.296875 2.460937 0 3 h -10.449218 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#e)" mask="url(#d)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 16 632 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#g)" mask="url(#f)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 17 631 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#i)" mask="url(#h)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 18 634 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#k)" mask="url(#j)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 16 634 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#m)" mask="url(#l)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 17 635 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#o)" mask="url(#n)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 19 635 h 1 v 1 h -1 z m 0 0" fill="#2e3436" fill-rule="evenodd"/>
+    </g>
+    <g clip-path="url(#q)" mask="url(#p)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 136 660 v 7 h 7 v -7 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#s)" mask="url(#r)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 199 642 h 3 v 12 h -3 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#u)" mask="url(#t)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 209.5 144.160156 c 0.277344 0 0.5 0.222656 0.5 0.5 v 1 c 0 0.277344 -0.222656 0.5 -0.5 0.5 s -0.5 -0.222656 -0.5 -0.5 v -1 c 0 -0.277344 0.222656 -0.5 0.5 -0.5 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#w)" mask="url(#v)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 206.5 144.160156 c 0.277344 0 0.5 0.222656 0.5 0.5 v 1 c 0 0.277344 -0.222656 0.5 -0.5 0.5 s -0.5 -0.222656 -0.5 -0.5 v -1 c 0 -0.277344 0.222656 -0.5 0.5 -0.5 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#y)" mask="url(#x)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 229.5 143.160156 c -0.546875 0 -1 0.457032 -1 1 c 0 0.546875 0.453125 1 1 1 s 1 -0.453125 1 -1 c 0 -0.542968 -0.453125 -1 -1 -1 z m 0 0" fill="#2e3436"/>
+    </g>
+    <g clip-path="url(#A)" mask="url(#z)" transform="matrix(1 0 0 1 -620 -624)">
+        <path d="m 226.453125 143.160156 c -0.519531 0 -0.953125 0.433594 -0.953125 0.953125 v 0.09375 c 0 0.519531 0.433594 0.953125 0.953125 0.953125 h 0.09375 c 0.519531 0 0.953125 -0.433594 0.953125 -0.953125 v -0.09375 c 0 -0.519531 -0.433594 -0.953125 -0.953125 -0.953125 z m 0 0" fill="#2e3436"/>
+    </g>
+</svg>
diff --git a/resources/resources.gresource.xml b/resources/resources.gresource.xml
index 092aed1..f52bb76 100644
--- a/resources/resources.gresource.xml
+++ b/resources/resources.gresource.xml
@@ -10,5 +10,6 @@
 		<file preprocess="xml-stripblanks">checkerboard-symbolic.svg</file>
 		<file preprocess="xml-stripblanks">heal-symbolic.svg</file>
 		<file preprocess="xml-stripblanks">info-symbolic.svg</file>
+		<file preprocess="xml-stripblanks">pin2-symbolic.svg</file>
 	</gresource>
 </gresources>