Diff: GraphicsDisplay.h

Revision:

34:c99ec28fac66

Parent:

33:b6b710758ab3

Child:

35:7dcab9e3ab25

--- a/GraphicsDisplay.h	Wed Jan 22 03:50:55 2014 +0000
+++ b/GraphicsDisplay.h	Thu Jan 23 23:45:20 2014 +0000
@@ -173,6 +173,24 @@
     ///         from the top down; as a result, it constantly 'seeks'
     ///         on the file system for the next row of information.
     ///
+    /// As a performance test, a sample picture was timed. A family picture
+    /// was converted to Bitmap format; shrunk to 352 x 272 pixels and save
+    /// in 8-bit color format. The resulting file size was 94.5 KByte.
+    /// The SPI port interface was set to 20 MHz.
+    /// The original bitmap rendering software was purely in software, 
+    /// pushing 1 pixel at a time to the write function, which did use SPI
+    /// hardware (not pin wiggling) to transfer commands and data to the 
+    /// display. Then, the driver was improved to leverage the capability
+    /// of the derived display driver. As a final check, instead of the
+    /// [known slow] local file system, a randomly chosen USB stick was 
+    /// used. The performance results are impressive (but depend on the
+    /// listed factors). 
+    ///
+    /// File System     | Rendering Method | Rendering Time
+    /// LocalFileSystem | Software only    | 34 sec
+    /// LocalFileSystem | Hardware RA8875  | 9 sec
+    /// MSCFileSystem   | Hardware RA8875  | 3 sec
+    /// 
     /// @param x is the horizontal pixel coordinate
     /// @param y is the vertical pixel coordinate
     /// @param Name_BMP is the filename on the local file system.