fix surge-synthesizer#544 Inactive buttons [Linux] (surge-synthesizer…

…#588)

Solo, Mute, and other CSwitchControl buttons were inactive on Linux because CScalableBitmap returns size 0,0 for all bitmaps on Linux. This diff doesn't solve that problem but accommodates it by making CSwitchControl work like the other switch controls; using a constructor specified size (in this case the size of the view rectangle) to determine how much to translate the switching image. This makes solo, mute, and others work on Linux.

Closes surge-synthesizer#544 by making those buttons inactive.

src/common/gui/CSwitchControl.cpp

@@ -10,7 +10,8 @@ CSwitchControl::CSwitchControl(const CRect& size,
 {
    down = false;
    is_itype = false;
-}
+   heightOfSingleImage = size.getHeight(); 
+ }
 
 void CSwitchControl::draw(CDrawContext* dc)
 {
@@ -26,7 +27,7 @@ void CSwitchControl::draw(CDrawContext* dc)
       }
       else
       {
-         CPoint where(0, (down ? (pBackground->getHeight() / 2) : 0));
+         CPoint where(0, (down ? heightOfSingleImage : 0));
          pBackground->draw(dc, size, where, 0xff);
       }
    }

src/common/gui/CSwitchControl.h

@@ -23,6 +23,7 @@ class CSwitchControl : public VSTGUI::CControl
 
 private:
    bool down;
+   float heightOfSingleImage;
 
    CLASS_METHODS(CSwitchControl, VSTGUI::CControl)
 };