update

matrix/include/canvas.h

@@ -0,0 +1,52 @@
+// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
+// Copyright (C) 2014 Henner Zeller <h.zeller@acm.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation version 2.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://gnu.org/licenses/gpl-2.0.txt>
+
+#ifndef RPI_CANVAS_H
+#define RPI_CANVAS_H
+#include <stdint.h>
+
+namespace rgb_matrix {
+// An interface for things a Canvas can do. The RGBMatrix implements this
+// interface, so you can use it directly wherever a canvas is needed.
+//
+// This abstraction also allows you to e.g. create delegating
+// implementations that do a particular transformation, e.g. re-map
+// pixels (as you might lay out the physical RGB matrix in a different way),
+// compose images (OR, XOR, transparecy), scale, rotate, anti-alias or
+// translate coordinates in a funky way.
+//
+// It is a good idea to have your applications use the concept of
+// a Canvas to write the content to instead of directly using the RGBMatrix.
+class Canvas {
+public:
+  virtual ~Canvas() {}
+  virtual int width() const = 0;  // Pixels available in x direction.
+  virtual int height() const = 0; // Pixels available in y direction.
+
+  // Set pixel at coordinate (x,y) with given color. Pixel (0,0) is the
+  // top left corner.
+  // Each color is 8 bit (24bpp), 0 black, 255 brightest.
+  virtual void SetPixel(int x, int y,
+                        uint8_t red, uint8_t green, uint8_t blue) = 0;
+
+  // Clear screen to be all black.
+  virtual void Clear() = 0;
+
+  // Fill screen with given 24bpp color.
+  virtual void Fill(uint8_t red, uint8_t green, uint8_t blue) = 0;
+};
+
+}  // namespace rgb_matrix
+#endif  // RPI_CANVAS_H