drivers/displays/tft/controls/hsbchart.c

   1 /**************************************************************************/
   2 /*!
   3     @file     hsbchart.c
   4     @author   K. Townsend (microBuilder.eu)
   5
   6     @brief    Renders a hue/saturation/brightness chart
   7
   8     @section LICENSE
   9
  10     Software License Agreement (BSD License)
  11
  12     Copyright (c) 2012, K. Townsend
  13     All rights reserved.
  14
  15     Redistribution and use in source and binary forms, with or without
  16     modification, are permitted provided that the following conditions are met:
  17     1. Redistributions of source code must retain the above copyright
  18     notice, this list of conditions and the following disclaimer.
  19     2. Redistributions in binary form must reproduce the above copyright
  20     notice, this list of conditions and the following disclaimer in the
  21     documentation and/or other materials provided with the distribution.
  22     3. Neither the name of the copyright holders nor the
  23     names of its contributors may be used to endorse or promote products
  24     derived from this software without specific prior written permission.
  25
  26     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
  27     EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  28     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  29     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
  30     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  31     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  32     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  33     ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  35     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36 */
  37 /**************************************************************************/
  38 #include <string.h>
  39
  40 #include "hsbchart.h"
  41
  42 /**************************************************************************/
  43 /*!
  44     @brief  Draws a square HSB (hue, saturation, brightness) chart
  45
  46     @param[in]  x
  47                 Starting x co-ordinate
  48     @param[in]  y
  49                 Starting y co-ordinate
  50     @param[in]  size
  51                 Width/height of the chart
  52     @param[in]  baseColor
  53                 The fully saturated color to use for the chart
  54 */
  55 /**************************************************************************/
  56 void hsbchartRender(uint16_t x, uint16_t y, uint16_t size, uint16_t baseColor, theme_t theme)
  57 {
  58   uint32_t delta;   // Alpha channel difference per pixel
  59   uint16_t colorS;  // Alpha-blended color for saturation
  60   uint16_t color;   // Alpha-blended color for saturation + brightness
  61   uint32_t b;       // Brightness counter
  62   uint32_t s;       // Saturation counter
  63
  64   drawRectangle(x, y, x+size, y+size, theme.colorBorderDarker);
  65
  66   if (size > 2)
  67   {
  68     delta = 10000/(size-2);       // Calculate difference in perfect per pixel (fixed point math, * 100)
  69     for (b = 0; b<size-1; b++)
  70     {
  71       // Calculate color for saturation
  72       colorS = colorsAlphaBlend(COLOR_WHITE, baseColor, 100 - (b*delta) / 100);
  73       for (s = 0; s<size-1; s++)
  74       {
  75         // Calculate color for brightness
  76         color = colorsAlphaBlend(colorS, COLOR_BLACK, 100 - (s*delta) / 100);
  77         drawPixel(x+b+1, y+s+1, color);
  78       }
  79     }
  80   }
  81 }