--- /dev/null
+/**************************************************************************/
+/*!
+ @file colors.c
+ @author K. Townsend (microBuilder.eu)
+
+ Various helper functions to work with RGB565 colors, including
+ color conversion, color blending, and a basic set of predefined
+ color constants (see colors.h).
+
+ @section LICENSE
+
+ Software License Agreement (BSD License)
+
+ Copyright (c) 2012, Kevin Townsend
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ 3. Neither the name of the copyright holders nor the
+ names of its contributors may be used to endorse or promote products
+ derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
+ EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
+ DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+/**************************************************************************/
+#include <string.h>
+
+#include "colors.h"
+
+/**************************************************************************/
+/* */
+/* ----------------------- Private Methods ------------------------------ */
+/* */
+/**************************************************************************/
+
+/**************************************************************************/
+/* */
+/* ----------------------- Public Methods ------------------------------- */
+/* */
+/**************************************************************************/
+
+/**************************************************************************/
+/*!
+ @brief Converts a 24-bit RGB color to an equivalent 16-bit RGB565 value
+
+ @param[in] r
+ 8-bit red
+ @param[in] g
+ 8-bit green
+ @param[in] b
+ 8-bit blue
+
+ @section Example
+
+ @code
+
+ // Get 16-bit equivalent of 24-bit color
+ uint16_t gray = colorsRGB24toRGB565(0x33, 0x33, 0x33);
+
+ @endcode
+*/
+/**************************************************************************/
+uint16_t colorsRGB24toRGB565(uint8_t r, uint8_t g, uint8_t b)
+{
+ return ((r / 8) << 11) | ((g / 4) << 5) | (b / 8);
+}
+
+/**************************************************************************/
+/*!
+ @brief Converts a 16-bit RGB565 color to a standard 32-bit BGRA32
+ color (with alpha set to 0xFF)
+
+ @param[in] color
+ 16-bit rgb565 color
+
+ @section Example
+
+ @code
+
+ // First convert 24-bit color to RGB565
+ uint16_t rgb565 = colorsRGB24toRGB565(0xFF, 0x00, 0x00);
+
+ // Convert RGB565 color back to BGRA32
+ uint32_t bgra32 = colorsRGB565toBGRA32(rgb565);
+
+ // Display results
+ printf("BGRA32: 0x%08X R: %u G: %u B: %u A: %u \r\n",
+ bgra32,
+ (bgra32 & 0x000000FF), // Blue
+ (bgra32 & 0x0000FF00) >> 8, // Green
+ (bgra32 & 0x00FF0000) >> 16, // Red
+ (bgra32 & 0xFF000000) >> 24); // Alpha
+
+ @endcode
+*/
+/**************************************************************************/
+uint32_t colorsRGB565toBGRA32(uint16_t color)
+{
+ uint32_t bits = (uint32_t)color;
+ uint32_t blue = bits & 0x001F; // 5 bits blue
+ uint32_t green = bits & 0x07E0; // 6 bits green
+ uint32_t red = bits & 0xF800; // 5 bits red
+
+ // Return shifted bits with alpha set to 0xFF
+ return (red << 8) | (green << 5) | (blue << 3) | 0xFF000000;
+}
+
+/**************************************************************************/
+/*!
+ @brief Reverses a 16-bit color from BGR to RGB or vice verse
+*/
+/**************************************************************************/
+uint16_t colorsBGR2RGB(uint16_t color)
+{
+ uint16_t r, g, b;
+
+ b = (color>>0) & 0x1f;
+ g = (color>>5) & 0x3f;
+ r = (color>>11) & 0x1f;
+
+ return( (b<<11) + (g<<5) + (r<<0) );
+}
+
+/**************************************************************************/
+/*!
+ @brief Adjusts the supplied color to have the specified intensity
+ (0..100). 100 will leave the color as is at full intensity,
+ 50 will reduce the color intensity by half, and 0 will return
+ black.
+
+ This function is useful for anti-aliasing and sub-pixel
+ rendering since colors are returned as a percentage of
+ the original value, depending on the amount of space they
+ take up in the sub-pixel array.
+
+ @param[in] color
+ Base color (rgb565)
+ @param[in] intensity
+ Color intensity relative to the source (0..100)
+
+ @section Example
+
+ @code
+
+ #include "drivers/displays/tft/colors.h"
+
+ uint16_t newColor;
+
+ // Draw a pure red rectangle
+ drawRectangleFilled(10, 10, 200, 100, COLOR_RED);
+
+ // Draw a rectangle at 50% intensity red
+ newColor = colorsDim(COLOR_RED, 50);
+ drawRectangleFilled(20, 20, 190, 90, newColor);
+
+ // Draw a rectangle at 25% intensity red
+ newColor = colorsDim(COLOR_RED, 25);
+ drawRectangleFilled(30, 30, 180, 80, newColor);
+
+ // Draw a rectangle at 0% intensity red
+ newColor = colorsDim(COLOR_RED, 0);
+ drawRectangleFilled(40, 40, 170, 70, newColor);
+
+ @endcode
+*/
+/**************************************************************************/
+uint16_t colorsDim(uint16_t color, uint8_t intensity)
+{
+ uint16_t r, g, b; // Individual component colors
+
+ // Add intensity adjusted forecolor
+ r = ((((color >> 11) & 0x1F) * intensity) / 100) & 0x1F;
+ g = ((((color >> 5) & 0x3F) * intensity) / 100) & 0x3F;
+ b = (((color & 0x1F) * intensity) / 100) & 0x1F;
+
+ return (r << 11) | (g << 6) | b;
+}
+
+/**************************************************************************/
+/*!
+ @brief Returns an alpha-blended color based on the supplied bg color,
+ fore color, and intensity value (0..100).
+
+ This function is used when alpha-blending anti-aliased fonts
+ with an existing background image, amongst other things, and
+ can be used to create images that appear to be 'faded' or
+ semi-transparent, though at the expense of slow updates since
+ reading pixels from most LCD controllers is an extremely
+ expensive operation.
+
+ @param[in] bgColor
+ Background color (rgb565)
+ @param[in] foreColor
+ Forground color (rgb565)
+ @param[in] intensity
+ Intensity of the fore color for alpha-blending (0..100)
+
+ @section Example
+
+ @code
+
+ #include "drivers/displays/tft/colors.h"
+
+ uint16_t mixedColor;
+
+ // Alpha-blend white onto a black background at 50% intensity
+ mixedColor = colorsBlend(COLOR_BLACK, COLOR_WHITE, 50);
+
+ @endcode
+*/
+/**************************************************************************/
+uint16_t colorsBlend(uint16_t bgColor, uint16_t foreColor, uint8_t intensity)
+{
+ // Note: This algorithm is buggy and needs to be redone!
+
+ uint16_t br, bg, bb; // Background component colors
+ uint16_t fr, fg, fb; // Foreground component colors
+ uint16_t newr, newg, newb; // Blended component colors
+
+ if (intensity > 100)
+ {
+ intensity = 100;
+ }
+
+ // Short cut if the color is full intensity
+ if (intensity == 100)
+ return foreColor;
+
+ // Break out component colors
+ br = ((bgColor >> 11) & 0x1F);
+ fr = ((foreColor >> 11) & 0x1F);
+ bg = ((bgColor >> 5) & 0x3F);
+ fg = ((foreColor >> 5) & 0x3F);
+ bb = (bgColor & 0x1F);
+ fb = (foreColor & 0x1F);
+
+ newr = (((fr-br) * intensity) / 100 + br) & 0x1F;
+ newg = (((fg-bg) * intensity) / 100 + bg) & 0x3F;
+ newb = (((fb-bb) * intensity) / 100 + bb) & 0x1F;
+
+ return (newr << 11) | (newg << 6) | newb;
+}
projects / hackover2013-badge-firmware.git / blobdiff