Add option to reverse colors

src/app/ui/color_bar.cpp

@@ -245,12 +245,15 @@ void ColorBar::onPaletteButtonClick()
 
       Menu menu;
       MenuItem
+        rev("Reverse Colors"),
         hue("Sort by Hue"),
         sat("Sort by Saturation"),
         bri("Sort by Brightness"),
         lum("Sort by Luminance"),
         asc("Ascending"),
         des("Descending");
+      menu.addChild(&rev);
+      menu.addChild(new ui::Separator("", JI_HORIZONTAL));
       menu.addChild(&hue);
       menu.addChild(&sat);
       menu.addChild(&bri);
@@ -262,6 +265,7 @@ void ColorBar::onPaletteButtonClick()
       if (m_ascending) asc.setSelected(true);
       else des.setSelected(true);
 
+      rev.Click.connect(Bind<void>(&ColorBar::onReverseColors, this));
       hue.Click.connect(Bind<void>(&ColorBar::onSortBy, this, SortPaletteBy::HUE));
       sat.Click.connect(Bind<void>(&ColorBar::onSortBy, this, SortPaletteBy::SATURATION));
       bri.Click.connect(Bind<void>(&ColorBar::onSortBy, this, SortPaletteBy::VALUE));
@@ -396,6 +400,53 @@ void ColorBar::onPickSpectrum(const app::Color& color, ui::MouseButtons buttons)
   m_lock = false;
 }
 
+void ColorBar::onReverseColors()
+{
+  PaletteView::SelectedEntries entries;
+  m_paletteView.getSelectedEntries(entries);
+
+  // Count the number of selected entries.
+  int n = 0;
+  for (bool state : entries) {
+    if (state)
+      ++n;
+  }
+
+  // If there is just one selected color, we select sort them all.
+  if (n < 2) {
+    n = 0;
+    for (auto& state : entries) {
+      state = true;
+      ++n;
+    }
+  }
+
+  std::vector<int> mapToOriginal(n); // Maps index from selectedPalette -> palette
+  int i = 0, j = 0;
+  for (bool state : entries) {
+    if (state)
+      mapToOriginal[j++] = i;
+    ++i;
+  }
+
+  Remap remap(Palette::MaxColors);
+  i = 0;
+  j = n;
+  for (bool state : entries) {
+    if (state)
+      remap.map(i, mapToOriginal[--j]);
+    else
+      remap.map(i, i);
+    ++i;
+  }
+
+  Palette newPalette(*get_current_palette(), remap);
+  applyRemap(remap, &newPalette, "Reverse Colors");
+
+  set_current_palette(&newPalette, false);
+  getManager()->invalidate();
+}
+
 void ColorBar::onSortBy(SortPaletteBy channel)
 {
   PaletteView::SelectedEntries entries;
@@ -449,11 +500,9 @@ void ColorBar::onSortBy(SortPaletteBy channel)
 
   // Create a new palette and apply the remap. This is the final new
   // palette for the sprite.
-  Palette newPalette(palette);
-  for (int i=0; i<palette.size(); ++i)
-    newPalette.setEntry(remapOrig[i], palette.getEntry(i));
+  Palette newPalette(palette, remapOrig);
 
-  applyRemap(remapOrig, &newPalette, "Sort Palette");
+  applyRemap(remapOrig, &newPalette, "Sort Colors");
 
   set_current_palette(&newPalette, false);
   getManager()->invalidate();

src/app/ui/color_bar.h

@@ -66,6 +66,7 @@ namespace app {
     void onBgColorButtonChange(const app::Color& color);
     void onColorButtonChange(const app::Color& color);
     void onPickSpectrum(const app::Color& color, ui::MouseButtons buttons);
+    void onReverseColors();
     void onSortBy(doc::SortPaletteBy channel);
     void setAscending(bool ascending);
 

src/doc/palette.cpp

@@ -11,6 +11,7 @@
 #include "doc/palette.h"
 
 #include "doc/image.h"
+#include "doc/remap.h"
 
 #include <algorithm>
 #include <limits>
@@ -39,6 +40,18 @@ Palette::Palette(const Palette& palette)
   m_modifications = 0;
 }
 
+Palette::Palette(const Palette& palette, const Remap& remap)
+  : Object(palette)
+{
+  m_frame = palette.m_frame;
+
+  resize(palette.size());
+  for (int i=0; i<size(); ++i)
+    setEntry(remap[i], palette.getEntry(i));
+
+  m_modifications = 0;
+}
+
 Palette::~Palette()
 {
 }

src/doc/palette.h

@@ -17,12 +17,15 @@
 
 namespace doc {
 
+  class Remap;
+
   class Palette : public Object {
   public:
     enum { MaxColors = 256 };
 
     Palette(frame_t frame, int ncolors);
     Palette(const Palette& palette);
+    Palette(const Palette& palette, const Remap& remap);
     ~Palette();
 
     static Palette* createGrayscale();