234 lines
7.1 KiB
C
234 lines
7.1 KiB
C
/****************************************************************************
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* libs/libnx/nxglib/nxglib_runcopy.c
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*
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* Copyright (C) 2008-2011, 2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <stdint.h>
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#include <fixedmath.h>
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#include <nuttx/video/rgbcolors.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxglib_rgb24_blend and nxglib_rgb565_blend
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*
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* Description:
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* Blend a single RGB color component. This is *not* alpha blending:
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* component2 is assumed to be opaque and "under" a semi-transparent
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* component1.
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*
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* The frac1 value could be though as related to the 1/alpha value for
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* component1. However, the background, component2, is always treated as though
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* alpha == 1.
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*
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* This algorithm is used to handle endpoints as part of the
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* implementation of anti-aliasing without transparency.
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*
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* Input Parameters:
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* component1 - The semi-transparent, forground 8-bit color component
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* component2 - The opaque, background color component
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* frac1 - The fractional amount of component1 to blend into component2
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*
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* Returned Value:
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* The blended 8-bit color component.
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*
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****************************************************************************/
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#if !defined(CONFIG_NX_DISABLE_16BPP) || !defined(CONFIG_NX_DISABLE_24BPP) || \
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!defined(CONFIG_NX_DISABLE_32BPP)
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static uint8_t nxglib_blend_component(uint8_t component1, uint8_t component2,
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ub8_t frac1)
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{
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uint16_t blend;
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uint32_t blendb8;
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/* Use a uint32_t for the intermediate calculation. Due to rounding this
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* value could exceed ub8MAX (0xffff == 255.999..).
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*
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* Hmm.. that might not actually be possible but this gives me piece of
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* mind and there should not be any particular overhead on a 32-bit
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* processor.
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*/
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blendb8 = (uint32_t)((ub16_t)component1 * frac1) +
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(uint32_t)((ub16_t)component2 * (b8ONE - frac1)) +
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(uint32_t)b8HALF;
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/* Now we can snap it down to 16-bits and check for the overflow condition. */
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blend = ub8toi(blendb8);
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if (blend > 255)
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{
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blend = 255;
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}
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/* Return the blended value */
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return (uint8_t)blend;
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxglib_rgb24_blend and nxglib_rgb565_blend
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*
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* Description:
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* Blend a foreground color onto a background color. This is *not* alpha
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* blending: color2 is assumed to be opaque and "under" a semi-
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* transparent color1.
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*
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* The frac1 value could be though as related to the 1/alpha value for
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* color1. However, the background, color2, is always treated as though
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* alpha == 1.
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*
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* This algorithm is used to handle endpoints as part of the
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* implementation of anti-aliasing without transparency.
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*
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* Input Parameters:
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* color1 - The semi-transparent, forground color
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* color2 - The opaque, background color
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* frac1 - The fractional amount of color1 to blend into color2
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*
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* Returned Value:
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* The blended color, encoded just was the input color1 and color2
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*
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****************************************************************************/
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#if !defined(CONFIG_NX_DISABLE_24BPP) || !defined(CONFIG_NX_DISABLE_32BPP)
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uint32_t nxglib_rgb24_blend(uint32_t color1, uint32_t color2, ub16_t frac1)
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{
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uint8_t r;
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uint8_t g;
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uint8_t b;
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uint8_t bg;
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ub8_t fracb8;
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/* Convert the fraction to ub8_t. We don't need that much precision to
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* scale an 8-bit color component.
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*/
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fracb8 = ub16toub8(frac1);
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/* Some limit checks. Rounding in the b16 to b8 conversion could cause
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* the fraction exceed one; the loss of precision could cause small b16
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* values to convert to zero.
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*/
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if (fracb8 >= b8ONE)
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{
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return color1;
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}
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else if (fracb8 == 0)
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{
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return color2;
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}
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/* Separate and blend each component */
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r = RGB24RED(color1);
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bg = RGB24RED(color2);
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r = nxglib_blend_component(r, bg, fracb8);
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g = RGB24GREEN(color1);
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bg = RGB24GREEN(color2);
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g = nxglib_blend_component(g, bg, fracb8);
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b = RGB24BLUE(color1);
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bg = RGB24BLUE(color2);
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b = nxglib_blend_component(b, bg, fracb8);
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/* Recombine and return the blended value */
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return RGBTO24(r,g,b);
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}
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#endif
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#ifndef CONFIG_NX_DISABLE_16BPP
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uint16_t nxglib_rgb565_blend(uint16_t color1, uint16_t color2, ub16_t frac1)
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{
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uint8_t r;
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uint8_t g;
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uint8_t b;
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uint8_t bg;
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ub8_t fracb8;
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/* Convert the fraction to ub8_t. We don't need that much precision. */
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fracb8 = ub16toub8(frac1);
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/* Some limit checks */
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if (fracb8 >= b8ONE)
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{
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return color1;
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}
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else if (fracb8 == 0)
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{
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return color2;
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}
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/* Separate and blend each component */
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r = RGB16RED(color1);
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bg = RGB16RED(color2);
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r = nxglib_blend_component(r, bg, fracb8);
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g = RGB16GREEN(color1);
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bg = RGB16GREEN(color2);
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g = nxglib_blend_component(g, bg, fracb8);
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b = RGB16BLUE(color1);
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bg = RGB16BLUE(color2);
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b = nxglib_blend_component(b, bg, fracb8);
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/* Recombine and return the blended value */
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return RGBTO24(r,g,b);
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}
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#endif
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