[shotwell] Add contrast adjustments to settings

[Jens Georg <jensgeorg src gnome org>]

commit 36d0265618b504d1c1d6187bf04709dd60d0a9ce
Author: Josh Freeman <josh twilightedge com>
Date:   Sun Jul 3 20:44:04 2016 +0200

    Add contrast adjustments to settings
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=716660

 src/ColorTransformation.vala        |   47 +++++++++++++++++++++++++-
 src/editing_tools/EditingTools.vala |   63 ++++++++++++++++++++++++++++-------
 2 files changed, 97 insertions(+), 13 deletions(-)
---
diff --git a/src/ColorTransformation.vala b/src/ColorTransformation.vala
index a7b7452..435d3f4 100644
--- a/src/ColorTransformation.vala
+++ b/src/ColorTransformation.vala
@@ -227,7 +227,8 @@ public enum PixelTransformationType {
     TEMPERATURE,
     TINT,
     SATURATION,
-    EXPOSURE
+    EXPOSURE,
+    CONTRAST
 }
 
 public class PixelTransformationBundle {
@@ -263,6 +264,7 @@ public class PixelTransformationBundle {
         set(new TintTransformation(0.0f));
         set(new SaturationTransformation(0.0f));
         set(new ExposureTransformation(0.0f));
+        set(new ContrastTransformation(0.0f));
     }
     
     public void load(KeyValueMap store) {
@@ -278,6 +280,7 @@ public class PixelTransformationBundle {
         set(new TintTransformation(store.get_float("tint", 0.0f)));
         set(new SaturationTransformation(store.get_float("saturation", 0.0f)));
         set(new ExposureTransformation(store.get_float("exposure", 0.0f)));
+        set(new ContrastTransformation(store.get_float("contrast", 0.0f)));
     }
     
     public KeyValueMap save(string group) {
@@ -318,6 +321,11 @@ public class PixelTransformationBundle {
         assert(new_exposure_trans != null);
         store.set_float("exposure", new_exposure_trans.get_parameter());
         
+        ContrastTransformation? new_contrast_trans =
+            (ContrastTransformation) get_transformation(PixelTransformationType.CONTRAST);
+        assert(new_contrast_trans != null);
+        store.set_float("contrast", new_contrast_trans.get_parameter());
+
         return store;
     }
     
@@ -728,6 +736,42 @@ public class ExposureTransformation : RGBTransformation {
     }
 }
 
+public class ContrastTransformation : RGBTransformation {
+    public const float MIN_PARAMETER = -16.0f;
+    public const float MAX_PARAMETER = 16.0f;
+
+    const float MAX_CONTRAST_ADJUSTMENT = 0.5f;  // must be less than 1.0
+
+    float parameter;
+
+    public ContrastTransformation(float client_parameter) {
+        base(PixelTransformationType.CONTRAST);
+
+        parameter = client_parameter.clamp(MIN_PARAMETER, MAX_PARAMETER);
+
+        if (parameter != 0.0f) {
+
+            float contrast_adjustment = (parameter / 16.0f) * MAX_CONTRAST_ADJUSTMENT;
+            float component_coefficient = 1.0f + contrast_adjustment;
+            float component_offset = contrast_adjustment / -2.0f;
+
+            matrix_entries[0] = component_coefficient;
+            matrix_entries[5] = component_coefficient;
+            matrix_entries[10] = component_coefficient;
+
+            matrix_entries[3] = component_offset;
+            matrix_entries[7] = component_offset;
+            matrix_entries[11] = component_offset;
+
+            identity = false;
+        }
+    }
+
+    public float get_parameter() {
+        return parameter;
+    }
+}
+
 public class PixelTransformer {
     private Gee.ArrayList<PixelTransformation> transformations =
         new Gee.ArrayList<PixelTransformation>();
@@ -1511,6 +1555,7 @@ public PixelTransformationBundle create_auto_enhance_adjustments(Gdk.Pixbuf pixb
     adjustments.set(new TemperatureTransformation(0.0f));
     adjustments.set(new TintTransformation(0.0f));
     adjustments.set(new ExposureTransformation(0.0f));
+    adjustments.set(new ContrastTransformation(0.0f));
     adjustments.set(new SaturationTransformation(0.0f));
     
     return adjustments;
diff --git a/src/editing_tools/EditingTools.vala b/src/editing_tools/EditingTools.vala
index c61a38c..34e569e 100644
--- a/src/editing_tools/EditingTools.vala
+++ b/src/editing_tools/EditingTools.vala
@@ -2205,6 +2205,9 @@ public class AdjustTool : EditingTool {
         public Gtk.Scale exposure_slider = new Gtk.Scale.with_range(Gtk.Orientation.HORIZONTAL,
             ExposureTransformation.MIN_PARAMETER, ExposureTransformation.MAX_PARAMETER,
             1.0);
+        public Gtk.HScale contrast_slider = new Gtk.HScale.with_range(
+            ContrastTransformation.MIN_PARAMETER, ContrastTransformation.MAX_PARAMETER,
+            1.0);
         public Gtk.Scale saturation_slider = new Gtk.Scale.with_range(Gtk.Orientation.HORIZONTAL,
             SaturationTransformation.MIN_PARAMETER, SaturationTransformation.MAX_PARAMETER,
             1.0);
@@ -2244,19 +2247,27 @@ public class AdjustTool : EditingTool {
             exposure_slider.set_size_request(SLIDER_WIDTH, -1);
             exposure_slider.set_draw_value(false);
             exposure_slider.set_margin_right(0);
-            
+
+            Gtk.Label contrast_label = new Gtk.Label.with_mnemonic(_("Contrast:"));
+            contrast_label.set_alignment(0.0f, 0.5f);
+            slider_organizer.attach(contrast_label, 0, 1, 1, 1);
+            slider_organizer.attach(contrast_slider, 1, 1, 1, 1);
+            contrast_slider.set_size_request(SLIDER_WIDTH, -1);
+            contrast_slider.set_draw_value(false);
+            contrast_slider.set_margin_right(0);
+
             Gtk.Label saturation_label = new Gtk.Label.with_mnemonic(_("Saturation:"));
             saturation_label.set_alignment(0.0f, 0.5f);
-            slider_organizer.attach(saturation_label, 0, 1, 1, 1);
-            slider_organizer.attach(saturation_slider, 1, 1, 1, 1);
+            slider_organizer.attach(saturation_label, 0, 2, 1, 1);
+            slider_organizer.attach(saturation_slider, 1, 2, 1, 1);
             saturation_slider.set_size_request(SLIDER_WIDTH, -1);
             saturation_slider.set_draw_value(false);
             saturation_slider.set_margin_right(0);
 
             Gtk.Label tint_label = new Gtk.Label.with_mnemonic(_("Tint:"));
             tint_label.set_alignment(0.0f, 0.5f);
-            slider_organizer.attach(tint_label, 0, 2, 1, 1);
-            slider_organizer.attach(tint_slider, 1, 2, 1, 1);
+            slider_organizer.attach(tint_label, 0, 3, 1, 1);
+            slider_organizer.attach(tint_slider, 1, 3, 1, 1);
             tint_slider.set_size_request(SLIDER_WIDTH, -1);
             tint_slider.set_draw_value(false);
             tint_slider.set_margin_right(0);
@@ -2264,24 +2275,24 @@ public class AdjustTool : EditingTool {
             Gtk.Label temperature_label =
                 new Gtk.Label.with_mnemonic(_("Temperature:"));
             temperature_label.set_alignment(0.0f, 0.5f);
-            slider_organizer.attach(temperature_label, 0, 3, 1, 1);
-            slider_organizer.attach(temperature_slider, 1, 3, 1, 1);
+            slider_organizer.attach(temperature_label, 0, 4, 1, 1);
+            slider_organizer.attach(temperature_slider, 1, 4, 1, 1);
             temperature_slider.set_size_request(SLIDER_WIDTH, -1);
             temperature_slider.set_draw_value(false);
             temperature_slider.set_margin_right(0);
 
             Gtk.Label shadows_label = new Gtk.Label.with_mnemonic(_("Shadows:"));
             shadows_label.set_alignment(0.0f, 0.5f);
-            slider_organizer.attach(shadows_label, 0, 4, 1, 1);
-            slider_organizer.attach(shadows_slider, 1, 4, 1, 1);
+            slider_organizer.attach(shadows_label, 0, 5, 1, 1);
+            slider_organizer.attach(shadows_slider, 1, 5, 1, 1);
             shadows_slider.set_size_request(SLIDER_WIDTH, -1);
             shadows_slider.set_draw_value(false);
             shadows_slider.set_margin_right(0);
 
             Gtk.Label highlights_label = new Gtk.Label.with_mnemonic(_("Highlights:"));
             highlights_label.set_alignment(0.0f, 0.5f);
-            slider_organizer.attach(highlights_label, 0, 5, 1, 1);
-            slider_organizer.attach(highlights_slider, 1, 5, 1, 1);
+            slider_organizer.attach(highlights_label, 0, 6, 1, 1);
+            slider_organizer.attach(highlights_slider, 1, 6, 1, 1);
             highlights_slider.set_size_request(SLIDER_WIDTH, -1);
             highlights_slider.set_draw_value(false);
 
@@ -2482,6 +2493,7 @@ public class AdjustTool : EditingTool {
     private bool disable_histogram_refresh = false;
     private OneShotScheduler? temperature_scheduler = null;
     private OneShotScheduler? tint_scheduler = null;
+    private OneShotScheduler? contrast_scheduler = null;
     private OneShotScheduler? saturation_scheduler = null;
     private OneShotScheduler? exposure_scheduler = null;
     private OneShotScheduler? shadows_scheduler = null;
@@ -2552,6 +2564,12 @@ public class AdjustTool : EditingTool {
         histogram_transformer.attach_transformation(exposure_trans);
         adjust_tool_window.exposure_slider.set_value(exposure_trans.get_parameter());
 
+        /* set up contrast */
+        ContrastTransformation contrast_trans = (ContrastTransformation)
+            transformations.get_transformation(PixelTransformationType.CONTRAST);
+        histogram_transformer.attach_transformation(contrast_trans);
+        adjust_tool_window.contrast_slider.set_value(contrast_trans.get_parameter());
+
         bind_canvas_handlers(canvas);
         bind_window_handlers();
 
@@ -2690,7 +2708,6 @@ public class AdjustTool : EditingTool {
     private void on_tint_adjustment() {
         if (tint_scheduler == null)
             tint_scheduler = new OneShotScheduler("tint", on_delayed_tint_adjustment);
-
         tint_scheduler.after_timeout(SLIDER_DELAY_MSEC, true);
     }
 
@@ -2700,6 +2717,19 @@ public class AdjustTool : EditingTool {
         slider_updated(new_tint_trans, _("Tint"));
     }
 
+    private void on_contrast_adjustment() {
+        if (this.contrast_scheduler == null)
+            this.contrast_scheduler = new OneShotScheduler("contrast", on_delayed_contrast_adjustment);
+        this.contrast_scheduler.after_timeout(SLIDER_DELAY_MSEC, true);
+    }
+
+    private void on_delayed_contrast_adjustment() {
+        ContrastTransformation new_exp_trans = new ContrastTransformation(
+            (float) adjust_tool_window.contrast_slider.get_value());
+        slider_updated(new_exp_trans, _("Contrast"));
+    }
+
+
     private void on_saturation_adjustment() {
         if (saturation_scheduler == null)
             saturation_scheduler = new OneShotScheduler("saturation", on_delayed_saturation_adjustment);
@@ -2794,6 +2824,7 @@ public class AdjustTool : EditingTool {
         adjust_tool_window.reset_button.clicked.connect(on_reset);
         adjust_tool_window.cancel_button.clicked.connect(notify_cancel);
         adjust_tool_window.exposure_slider.value_changed.connect(on_exposure_adjustment);
+        adjust_tool_window.contrast_slider.value_changed.connect(on_contrast_adjustment);
         adjust_tool_window.saturation_slider.value_changed.connect(on_saturation_adjustment);
         adjust_tool_window.tint_slider.value_changed.connect(on_tint_adjustment);
         adjust_tool_window.temperature_slider.value_changed.connect(on_temperature_adjustment);
@@ -2803,6 +2834,7 @@ public class AdjustTool : EditingTool {
 
         adjust_tool_window.saturation_slider.button_press_event.connect(on_hscale_reset);
         adjust_tool_window.exposure_slider.button_press_event.connect(on_hscale_reset);
+        adjust_tool_window.contrast_slider.button_press_event.connect(on_hscale_reset);
         adjust_tool_window.tint_slider.button_press_event.connect(on_hscale_reset);
         adjust_tool_window.temperature_slider.button_press_event.connect(on_hscale_reset);
         adjust_tool_window.shadows_slider.button_press_event.connect(on_hscale_reset);
@@ -2814,6 +2846,7 @@ public class AdjustTool : EditingTool {
         adjust_tool_window.reset_button.clicked.disconnect(on_reset);
         adjust_tool_window.cancel_button.clicked.disconnect(notify_cancel);
         adjust_tool_window.exposure_slider.value_changed.disconnect(on_exposure_adjustment);
+        adjust_tool_window.contrast_slider.value_changed.disconnect(on_contrast_adjustment);
         adjust_tool_window.saturation_slider.value_changed.disconnect(on_saturation_adjustment);
         adjust_tool_window.tint_slider.value_changed.disconnect(on_tint_adjustment);
         adjust_tool_window.temperature_slider.value_changed.disconnect(on_temperature_adjustment);
@@ -2823,6 +2856,7 @@ public class AdjustTool : EditingTool {
 
         adjust_tool_window.saturation_slider.button_press_event.disconnect(on_hscale_reset);
         adjust_tool_window.exposure_slider.button_press_event.disconnect(on_hscale_reset);
+        adjust_tool_window.contrast_slider.button_press_event.disconnect(on_hscale_reset);
         adjust_tool_window.tint_slider.button_press_event.disconnect(on_hscale_reset);
         adjust_tool_window.temperature_slider.button_press_event.disconnect(on_hscale_reset);
         adjust_tool_window.shadows_slider.button_press_event.disconnect(on_hscale_reset);
@@ -2877,6 +2911,11 @@ public class AdjustTool : EditingTool {
             break;
 
             case PixelTransformationType.HIGHLIGHTS:
+                adjust_tool_window.contrast_slider.set_value(
+                    ((ContrastTransformation) transformation).get_parameter());
+            break;
+
+            case PixelTransformationType.CONTRAST:
                 adjust_tool_window.highlights_slider.set_value(
                     ((HighlightDetailTransformation) transformation).get_parameter());
             break;