Diff: GraphicsDisplay.h

Revision:

142:6e9bff59878a

Parent:

136:224e03d5c31f

Child:

143:e872d65a710d

--- a/GraphicsDisplay.h	Thu Dec 29 20:06:00 2016 +0000
+++ b/GraphicsDisplay.h	Sun Mar 19 21:41:24 2017 +0000
@@ -147,6 +147,54 @@
     virtual RetCode_t fillrect(loc_t x1, loc_t y1, loc_t x2, loc_t y2, 
         color_t color, fill_t fillit = FILL) = 0;
 
+    /// Select the drawing layer for subsequent commands.
+    ///
+    /// If the screen configuration is 480 x 272, or if it is 800 x 480 
+    /// and 8-bit color, the the display supports two layers, which can 
+    /// be independently drawn on and shown. Additionally, complex
+    /// operations involving both layers are permitted.
+    ///
+    /// @code
+    ///     //lcd.SetLayerMode(OnlyLayer0); // default is layer 0
+    ///     lcd.rect(400,130, 475,155,Brown);
+    ///     lcd.SelectDrawingLayer(1);
+    ///     lcd.circle(400,25, 25, BrightRed);
+    ///     wait(1);
+    ///     lcd.SetLayerMode(ShowLayer1);
+    /// @endcode
+    ///
+    /// @attention The user manual refers to Layer 1 and Layer 2, however the
+    ///     actual register values are value 0 and 1. This API as well as
+    ///     others that reference the layers use the values 0 and 1 for
+    ///     cleaner iteration in the code.
+    ///
+    /// @param[in] layer is 0 or 1 to select the layer for subsequent 
+    ///     commands.
+    /// @returns the previous drawing layer; 0 or 1.
+    ///
+    virtual uint16_t SelectDrawingLayer(uint16_t layer) = 0;
+ 
+    
+    /// Get the currently active drawing layer.
+    ///
+    /// This returns a value, 0 or 1, based on the screen configuration
+    /// and the currently active drawing layer.
+    ///
+    /// @code
+    ///     uint16_t prevLayer = lcd.SelectDrawingLayer(x);
+    ///     lcd.circle(400,25, 25, BrightRed);
+    ///     lcd.SelectDrawingLayer(prevLayer);
+    /// @endcode
+    ///
+    /// @attention The user manual refers to Layer 1 and Layer 2, however the
+    ///     actual register values are value 0 and 1. This API as well as
+    ///     others that reference the layers use the values 0 and 1 for
+    ///     cleaner iteration in the code.
+    ///
+    /// @returns the current drawing layer; 0 or 1.
+    /// 
+    virtual uint16_t GetDrawingLayer(void) = 0;
+
     /// a function to write the command and data to the RA8875 chip.
     ///
     /// @param command is the RA8875 instruction to perform