Added a minimum alpha opacity value handle in SkinLoader and made use of it.

Part 1 of 3 for Mantis #847
Only a few controls follow minimum opacity value at login stage.
Part 2 will make all other controls do the same.
Part 3 will try to set default gui opacity value as a constant.

7 files changed, 86 insertions, 30 deletions

diff --git a/src/gui/skin.cpp b/src/gui/skin.cpp
index 5881a073..f3f907e1 100644
--- a/src/gui/skin.cpp
+++ b/src/gui/skin.cpp
@@ -87,9 +87,10 @@ Skin::~Skin()
     delete mStickyImageDown;
 }
 
-void Skin::updateAlpha()
+void Skin::updateAlpha(float minimumOpacityAllowed)
 {
-    const float alpha = config.getValue("guialpha", 0.8);
+    const float alpha = std::max((double)minimumOpacityAllowed,
+                                 config.getValue("guialpha", 0.8f));
 
     for_each(mBorder.grid, mBorder.grid + 9,
              std::bind2nd(std::mem_fun(&Image::setAlpha), alpha));
@@ -112,7 +113,8 @@ int Skin::getMinHeight() const
 }
 
 SkinLoader::SkinLoader()
-    : mSkinConfigListener(new SkinConfigListener(this))
+    : mSkinConfigListener(new SkinConfigListener(this)),
+    mMinimumOpacity(-1.0f)
 {
 }
 
@@ -174,10 +176,18 @@ Skin *SkinLoader::load(const std::string &filename,
     return skin;
 }
 
+void SkinLoader::setMinimumOpacity(float minimumOpacity)
+{
+    if (minimumOpacity > 1.0f) return;
+
+    mMinimumOpacity = minimumOpacity;
+    updateAlpha();
+}
+
 void SkinLoader::updateAlpha()
 {
     for (SkinIterator iter = mSkins.begin(); iter != mSkins.end(); ++iter)
-        iter->second->updateAlpha();
+        iter->second->updateAlpha(mMinimumOpacity);
 }
 
 Skin *SkinLoader::readSkin(const std::string &filename)
@@ -284,6 +294,6 @@ Skin *SkinLoader::readSkin(const std::string &filename)
 
     Skin *skin = new Skin(border, closeImage, stickyImageUp, stickyImageDown,
                           filename);
-    skin->updateAlpha();
+    skin->updateAlpha(mMinimumOpacity);
     return skin;
 }
diff --git a/src/gui/skin.h b/src/gui/skin.h
index c56072d3..5f612c26 100644
--- a/src/gui/skin.h
+++ b/src/gui/skin.h
@@ -82,7 +82,7 @@ class Skin
         /**
          * Updates the alpha value of the skin
          */
-        void updateAlpha();
+        void updateAlpha(float minimumOpacityAllowed = 0.0f);
 
         int instances;
 
@@ -95,7 +95,7 @@ class Skin
         Image *mStickyImageDown;   /**< Sticky Button Image */
 };
 
-class SkinLoader 
+class SkinLoader
 {
     public:
         static SkinLoader *instance();
@@ -112,6 +112,18 @@ class SkinLoader
          */
         void updateAlpha();
 
+        /**
+         * Get the minimum opacity allowed to skins.
+         */
+        float getMinimumOpacity()
+        { return mMinimumOpacity; }
+
+        /**
+         * Set the minimum opacity allowed to skins.
+         * Set a negative value to free the minimum allowed.
+         */
+        void setMinimumOpacity(float minimumOpacity);
+
     private:
         SkinLoader();
         ~SkinLoader();
@@ -130,6 +142,12 @@ class SkinLoader
         ConfigListener *mSkinConfigListener;
 
         static SkinLoader *mInstance;
+
+        /**
+         * Tells if the current skins opacity
+         * should not get less than the given value
+         */
+        float mMinimumOpacity;
 };
 
 #endif
diff --git a/src/gui/widgets/button.cpp b/src/gui/widgets/button.cpp
index 2357b263..9f44cdfc 100644
--- a/src/gui/widgets/button.cpp
+++ b/src/gui/widgets/button.cpp
@@ -28,6 +28,7 @@
 
 #include "resources/image.h"
 #include "resources/resourcemanager.h"
+#include "gui/skin.h"
 
 #include "utils/dtor.h"
 
@@ -101,12 +102,12 @@ void Button::init()
                             data[x].gridX, data[y].gridY,
                             data[x + 1].gridX - data[x].gridX + 1,
                             data[y + 1].gridY - data[y].gridY + 1);
-                    button[mode].grid[a]->setAlpha(mAlpha);
                     a++;
                 }
             }
             btn[mode]->decRef();
         }
+        updateAlpha();
     }
     mInstances++;
 }
@@ -124,6 +125,24 @@ Button::~Button()
     }
 }
 
+void Button::updateAlpha()
+{
+    float alpha = std::max(config.getValue("guialpha", 0.8f),
+                           (double)SkinLoader::instance()->getMinimumOpacity());
+
+    if (mAlpha != alpha)
+    {
+        mAlpha = alpha;
+        for (int a = 0; a < 9; a++)
+        {
+            button[BUTTON_DISABLED].grid[a]->setAlpha(mAlpha);
+            button[BUTTON_PRESSED].grid[a]->setAlpha(mAlpha);
+            button[BUTTON_HIGHLIGHTED].grid[a]->setAlpha(mAlpha);
+            button[BUTTON_STANDARD].grid[a]->setAlpha(mAlpha);
+        }
+    }
+}
+
 void Button::draw(gcn::Graphics *graphics)
 {
     int mode;
@@ -137,17 +156,7 @@ void Button::draw(gcn::Graphics *graphics)
     else
         mode = BUTTON_STANDARD;
 
-    if (config.getValue("guialpha", 0.8) != mAlpha)
-    {
-        mAlpha = config.getValue("guialpha", 0.8);
-        for (int a = 0; a < 9; a++)
-        {
-            button[BUTTON_DISABLED].grid[a]->setAlpha(mAlpha);
-            button[BUTTON_PRESSED].grid[a]->setAlpha(mAlpha);
-            button[BUTTON_HIGHLIGHTED].grid[a]->setAlpha(mAlpha);
-            button[BUTTON_STANDARD].grid[a]->setAlpha(mAlpha);
-        }
-    }
+    updateAlpha();
 
     static_cast<Graphics*>(graphics)->
         drawImageRect(0, 0, getWidth(), getHeight(), button[mode]);
diff --git a/src/gui/widgets/button.h b/src/gui/widgets/button.h
index eebf7931..7eb7e2ef 100644
--- a/src/gui/widgets/button.h
+++ b/src/gui/widgets/button.h
@@ -56,6 +56,11 @@ class Button : public gcn::Button
          */
         void draw(gcn::Graphics *graphics);
 
+        /**
+         * Update the alpha value to the button components.
+         */
+        void updateAlpha();
+
     private:
         void init();
 
diff --git a/src/gui/widgets/checkbox.cpp b/src/gui/widgets/checkbox.cpp
index dd57f674..9b4ab2f4 100644
--- a/src/gui/widgets/checkbox.cpp
+++ b/src/gui/widgets/checkbox.cpp
@@ -28,6 +28,7 @@
 
 #include "resources/image.h"
 #include "resources/resourcemanager.h"
+#include "gui/skin.h"
 
 int CheckBox::instances = 0;
 float CheckBox::mAlpha = 1.0;
@@ -91,6 +92,23 @@ void CheckBox::draw(gcn::Graphics* graphics)
     graphics->drawText(getCaption(), h - 2, 0);
 }
 
+void CheckBox::updateAlpha()
+{
+    float alpha = std::max(config.getValue("guialpha", 0.8f),
+                       (double)SkinLoader::instance()->getMinimumOpacity());
+
+    if (mAlpha != alpha)
+    {
+        mAlpha = alpha;
+        checkBoxNormal->setAlpha(mAlpha);
+        checkBoxChecked->setAlpha(mAlpha);
+        checkBoxDisabled->setAlpha(mAlpha);
+        checkBoxDisabledChecked->setAlpha(mAlpha);
+        checkBoxNormal->setAlpha(mAlpha);
+        checkBoxCheckedHi->setAlpha(mAlpha);
+    }
+}
+
 void CheckBox::drawBox(gcn::Graphics* graphics)
 {
     Image *box;
@@ -112,16 +130,7 @@ void CheckBox::drawBox(gcn::Graphics* graphics)
         else
             box = checkBoxDisabled;
 
-    if (config.getValue("guialpha", 0.8) != mAlpha)
-    {
-        mAlpha = config.getValue("guialpha", 0.8);
-        checkBoxNormal->setAlpha(mAlpha);
-        checkBoxChecked->setAlpha(mAlpha);
-        checkBoxDisabled->setAlpha(mAlpha);
-        checkBoxDisabledChecked->setAlpha(mAlpha);
-        checkBoxNormal->setAlpha(mAlpha);
-        checkBoxCheckedHi->setAlpha(mAlpha);
-    }
+    updateAlpha();
 
     static_cast<Graphics*>(graphics)->drawImage(box, 2, 2);
 }
diff --git a/src/gui/widgets/checkbox.h b/src/gui/widgets/checkbox.h
index 7a7c8674..a65a5196 100644
--- a/src/gui/widgets/checkbox.h
+++ b/src/gui/widgets/checkbox.h
@@ -51,6 +51,11 @@ class CheckBox : public gcn::CheckBox
         void draw(gcn::Graphics* graphics);
 
         /**
+         * Update the alpha value to the checkbox components.
+         */
+        void updateAlpha();
+
+        /**
          * Draws the check box, not the caption.
          */
         void drawBox(gcn::Graphics* graphics);
diff --git a/src/gui/widgets/window.cpp b/src/gui/widgets/window.cpp
index 1ee84a6f..9c098bdb 100644
--- a/src/gui/widgets/window.cpp
+++ b/src/gui/widgets/window.cpp
@@ -750,7 +750,7 @@ void Window::center()
 void Window::checkIfIsOffScreen(bool partially, bool entirely)
 {
     // Move the window onto screen if it has become off screen
-    // For instance, because of resolution change... 
+    // For instance, because of resolution change...
 
     // First of all, don't deal when a window hasn't got
     // any size initialized yet...