Draw alpha slider in ColorSliders correctly

src/app/modules/gfx.cpp

@@ -21,26 +21,34 @@
 #include "app/modules/palettes.h"
 #include "app/ui/editor/editor.h"
 #include "app/ui/skin/skin_theme.h"
-#include "gfx/point.h"
-#include "gfx/rect.h"
+#include "doc/blend_funcs.h"
 #include "doc/image.h"
 #include "doc/palette.h"
+#include "gfx/point.h"
+#include "gfx/rect.h"
 
 namespace app {
 
 using namespace app::skin;
 using namespace gfx;
 
+namespace {
+
+// TODO hard-coded values, use pref.xml values
+gfx::Color gridColor1 = gfx::rgba(128, 128, 128);
+gfx::Color gridColor2 = gfx::rgba(192, 192, 192);
+
+} // anonymous namespace
+
 static void rectgrid(ui::Graphics* g, const gfx::Rect& rc, const gfx::Size& tile)
 {
   if (tile.w < 1 || tile.h < 1)
     return;
 
   int x, y, u, v;
 
-  // TODO these values are hard-coded in ColorSelector::onPaintAlphaBar() too, use pref.xml values
-  gfx::Color c1 = gfx::rgba(128, 128, 128);
-  gfx::Color c2 = gfx::rgba(192, 192, 192);
+  const gfx::Color c1 = gridColor1;
+  const gfx::Color c2 = gridColor2;
 
   u = 0;
   v = 0;
@@ -147,4 +155,30 @@ void draw_color_button(ui::Graphics* g,
   }
 }
 
+void draw_alpha_slider(ui::Graphics* g,
+                       const gfx::Rect& rc,
+                       const app::Color& color)
+{
+  const int xmax = MAX(1, rc.w-1);
+  const doc::color_t c =
+    (color.getType() != app::Color::MaskType ?
+     doc::rgba(color.getRed(),
+               color.getGreen(),
+               color.getBlue(), 255): 0);
+
+  for (int x=0; x<rc.w; ++x) {
+    const int a = (255 * x / xmax);
+    const doc::color_t c1 = doc::rgba_blender_normal(gridColor1, c, a);
+    const doc::color_t c2 = doc::rgba_blender_normal(gridColor2, c, a);
+    const int mid = rc.h/2;
+    const int odd = (x / rc.h) & 1;
+    g->drawVLine(
+      app::color_utils::color_for_ui(app::Color::fromImage(IMAGE_RGB, odd ? c2: c1)),
+      rc.x+x, rc.y, mid);
+    g->drawVLine(
+      app::color_utils::color_for_ui(app::Color::fromImage(IMAGE_RGB, odd ? c1: c2)),
+      rc.x+x, rc.y+mid, rc.h-mid);
+  }
+}
+
 } // namespace app

src/app/modules/gfx.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2016  David Capello
+// Copyright (C) 2001-2017  David Capello
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -30,6 +30,10 @@ namespace app {
                          const bool hot,
                          const bool drag);
 
+  void draw_alpha_slider(ui::Graphics* g,
+                         const gfx::Rect& rc,
+                         const app::Color& color);
+
 } // namespace app
 
 #endif

src/app/ui/color_selector.cpp

@@ -11,10 +11,10 @@
 #include "app/ui/color_selector.h"
 
 #include "app/color_utils.h"
+#include "app/modules/gfx.h"
 #include "app/ui/skin/skin_theme.h"
 #include "app/ui/status_bar.h"
 #include "base/scoped_value.h"
-#include "doc/blend_funcs.h"
 #include "she/surface.h"
 #include "ui/manager.h"
 #include "ui/message.h"
@@ -202,32 +202,11 @@ void ColorSelector::onPaint(ui::PaintEvent& ev)
 
 void ColorSelector::onPaintAlphaBar(ui::Graphics* g, const gfx::Rect& rc)
 {
-  const int xmax = MAX(1, rc.w-1);
-  const int alpha = m_color.getAlpha();
-  const doc::color_t c =
-    (m_color.getType() != app::Color::MaskType ?
-     doc::rgba(m_color.getRed(),
-               m_color.getGreen(),
-               m_color.getBlue(), 255): 0);
-
-  for (int x=0; x<rc.w; ++x) {
-    const int a = (255 * x / xmax);
-
-    // TODO These values are hard-coded in rectgrid() (modules/gfx.cpp) too, use pref.xml values
-    const doc::color_t c1 = doc::rgba_blender_normal(gfx::rgba(128, 128, 128), c, a);
-    const doc::color_t c2 = doc::rgba_blender_normal(gfx::rgba(192, 192, 192), c, a);
-    const int mid = rc.h/2;
-    const int odd = (x / rc.h) & 1;
-    g->drawVLine(
-      app::color_utils::color_for_ui(app::Color::fromImage(IMAGE_RGB, odd ? c2: c1)),
-      rc.x+x, rc.y, mid);
-    g->drawVLine(
-      app::color_utils::color_for_ui(app::Color::fromImage(IMAGE_RGB, odd ? c1: c2)),
-      rc.x+x, rc.y+mid, rc.h-mid);
-  }
+  draw_alpha_slider(g, rc, m_color);
 
-  gfx::Point pos(rc.x + int(rc.w * alpha / 255),
-                 rc.y + rc.h/2);
+  const int alpha = m_color.getAlpha();
+  const gfx::Point pos(rc.x + int(rc.w * alpha / 255),
+                       rc.y + rc.h/2);
   paintColorIndicator(g, pos, false);
 }
 

src/app/ui/color_sliders.cpp

@@ -9,6 +9,7 @@
 #endif
 
 #include "app/color_utils.h"
+#include "app/modules/gfx.h"
 #include "app/ui/color_sliders.h"
 #include "app/ui/skin/skin_slider_property.h"
 #include "app/ui/skin/skin_theme.h"
@@ -48,6 +49,12 @@ namespace {
     }
 
     void paint(Slider* slider, Graphics* g, const gfx::Rect& rc) {
+      // Special alpha bar (with two vertical lines)
+      if (m_channel == ColorSliders::Alpha) {
+        draw_alpha_slider(g, rc, m_color);
+        return;
+      }
+
       gfx::Color color = gfx::ColorNone;
       int w = MAX(rc.w-1, 1);
 
@@ -102,7 +109,6 @@ namespace {
             break;
 
           case ColorSliders::Gray:
-          case ColorSliders::Alpha:
             color = color_utils::color_for_ui(
               app::Color::fromGray(255 * x / w));
             break;