#95106

r=pavlov, sr=waterson
Get 256 colors working again - step 1 - add back palette API to nsDeviceContext

gfx/public/nsDeviceContext.h

@@ -124,6 +124,8 @@ public:
 
   NS_IMETHOD GetDepth(PRUint32& aDepth);
 
+  NS_IMETHOD GetPaletteInfo(nsPaletteInfo& aPaletteInfo);
+
 #ifdef NS_PRINT_PREVIEW
   NS_IMETHOD SetAltDevice(nsIDeviceContext* aAltDC);
   NS_IMETHOD GetAltDevice(nsIDeviceContext** aAltDC) { *aAltDC = mAltDC.get(); NS_IF_ADDREF(*aAltDC); return NS_OK;}

gfx/public/nsIDeviceContext.h

@@ -111,6 +111,14 @@ const PRUint8 kUseAltDCFor_SURFACE_DIM = 0x04; // Use it for getting the Surface
 //a cross platform way of specifying a native palette handle
 typedef void * nsPalette;
 
+  //structure used to return information about a device's palette capabilities
+  struct nsPaletteInfo {
+     PRPackedBool  isPaletteDevice;
+     PRUint16      sizePalette;  // number of entries in the palette
+     PRUint16      numReserved;  // number of reserved palette entries
+     nsPalette     palette;      // native palette handle
+  };
+
   typedef enum {
     eSystemFont_Caption,         // css2
     eSystemFont_Icon,
@@ -342,6 +350,11 @@ public:
    */
   NS_IMETHOD GetDepth(PRUint32& aDepth) = 0;
 
+  /**
+   * Returns information about the device's palette capabilities.
+   */
+  NS_IMETHOD GetPaletteInfo(nsPaletteInfo& aPaletteInfo) = 0;
+
   /**
    * Returns Platform specific pixel value for an RGB value
    */

gfx/src/nsDeviceContext.cpp

@@ -360,6 +360,15 @@ NS_IMETHODIMP DeviceContextImpl::GetDepth(PRUint32& aDepth)
   return NS_OK;
 }
 
+NS_IMETHODIMP DeviceContextImpl::GetPaletteInfo(nsPaletteInfo& aPaletteInfo)
+{
+  aPaletteInfo.isPaletteDevice = PR_FALSE;
+  aPaletteInfo.sizePalette = 0;
+  aPaletteInfo.numReserved = 0;
+  aPaletteInfo.palette = nsnull;
+  return NS_OK;
+}
+
 struct FontEnumData {
   FontEnumData(nsIDeviceContext* aDC, nsString& aFaceName)
     : mDC(aDC), mFaceName(aFaceName)