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nuttx/graphics/nxglib/fb/nxglib_filltrapezoid.c

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/****************************************************************************
* graphics/nxglib/fb/nxglib_filltrapezoid.c
*
* Copyright (C) 2008-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 AND CONTRIBUTORS
* "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 OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <fixedmath.h>
#include <nuttx/video/fb.h>
#include <nuttx/nx/nxglib.h>
#include "nxglib_bitblit.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef NXGLIB_SUFFIX
# error "NXGLIB_SUFFIX must be defined before including this header file"
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxglib_filltrapezoid_*bpp
*
* Descripton:
* Fill a trapezoidal region in the framebuffer memory with a fixed color.
* Clip the trapezoid to lie within a boundng box. This is useful for
* drawing complex shapes that can be broken into a set of trapezoids.
*
****************************************************************************/
void NXGL_FUNCNAME(nxgl_filltrapezoid,NXGLIB_SUFFIX)(
FAR struct fb_planeinfo_s *pinfo,
FAR const struct nxgl_trapezoid_s *trap,
FAR const struct nxgl_rect_s *bounds,
NXGL_PIXEL_T color)
{
unsigned int stride;
unsigned int width;
FAR uint8_t *dest;
FAR uint8_t *line;
int nrows;
b16_t x1;
b16_t x2;
nxgl_coord_t y1;
nxgl_coord_t y2;
b16_t dx1dy;
b16_t dx2dy;
#if NXGLIB_BITSPERPIXEL < 8
uint8_t mpixel = NXGL_MULTIPIXEL(color);
uint8_t mask;
int lnlen;
#endif
/* Get the width of the framebuffer in bytes */
stride = pinfo->stride;
/* Get the top run position and the number of rows to draw */
x1 = trap->top.x1;
x2 = trap->top.x2;
/* Calculate the number of rows to render */
y1 = trap->top.y;
y2 = trap->bot.y;
nrows = y2 - y1 + 1;
/* Calculate the slope of the left and right side of the trapezoid */
if (nrows > 1)
{
dx1dy = b16divi((trap->bot.x1 - x1), nrows - 1);
dx2dy = b16divi((trap->bot.x2 - x2), nrows - 1);
}
else
{
/* The trapezoid is a run! Use the average width. */
x1 = (x1 + trap->bot.x1) >> 1;
x2 = (x2 + trap->bot.x2) >> 1;
dx1dy = 0;
dx2dy = 0;
}
/* Perform vertical clipping */
if (y1 < bounds->pt1.y)
{
/* Is the entire trapezoid "above" the clipping window? */
if (y2 < bounds->pt1.y)
{
/* Yes.. then do nothing */
return;
}
/* Calculate the x values for the new top run */
int dy = bounds->pt1.y - y1;
x1 += dy * dx1dy;
x2 += dy * dx2dy;
/* Clip and re-calculate the number of rows to render */
y1 = bounds->pt1.y;
nrows = y2 - y1 + 1;
}
if (y2 > bounds->pt2.y)
{
/* Is the entire trapezoid "below" the clipping window? */
if (y1 > bounds->pt2.y)
{
/* Yes.. then do nothing */
return;
}
/* Clip and re-calculate the number of rows to render */
y2 = bounds->pt2.y;
nrows = y2 - y1 + 1;
}
/* Get the address of the first byte on the first line */
line = pinfo->fbmem + y1 * stride ;
/* Then fill the trapezoid line-by-line */
while (nrows--)
{
int ix1;
int ix2;
/* Handle the special case where the sides cross (as in an hourglass) */
if (x1 > x2)
{
b16_t tmp;
ngl_swap(x1, x2, tmp);
ngl_swap(dx1dy, dx2dy, tmp);
}
/* Convert the positions to integer */
ix1 = b16toi(x1);
ix2 = b16toi(x2);
/* Handle some corner cases where we draw nothing. Otherwise, we will
* always draw at least one pixel.
*/
if (x1 <= x2 && ix2 >= bounds->pt1.x && ix1 <= bounds->pt2.x)
{
/* Get a clipped copies of the starting and ending X positions. This
* clipped truncates "down" and gives the quantized pixel holding the
* fractional X position
*/
ix1 = ngl_clipl(ix1, bounds->pt1.x);
ix2 = ngl_clipr(ix2, bounds->pt2.x);
/* Get the run length for the clipped row */
width = ix2 - ix1 + 1;
#if NXGLIB_BITSPERPIXEL < 8
/* Handle masking of the fractional initial byte */
#ifdef CONFIG_NX_PACKEDMSFIRST
mask = (uint8_t)(0xff >> (8 - NXGL_REMAINDERX(ix1)));
#else
mask = (uint8_t)(0xff << (8 - NXGL_REMAINDERX(ix1)));
#endif
dest = line;
lnlen = width;
if (lnlen > 1 && mask)
{
dest[0] = (dest[0] & ~mask) | (mpixel & mask);
mask = 0xff;
dest++;
lnlen--;
}
/* Handle masking of the fractional final byte */
#ifdef CONFIG_NX_PACKEDMSFIRST
mask &= (uint8_t)(0xff << (8 - NXGL_REMAINDERX(ix2)));
#else
mask &= (uint8_t)(0xff >> (8 - NXGL_REMAINDERX(ix2)));
#endif
if (lnlen > 0 && mask)
{
dest[lnlen-1] = (dest[lnlen-1] & ~mask) | (mpixel & mask);
lnlen--;
}
/* Handle all of the unmasked bytes in-between */
if (lnlen > 0)
{
NXGL_MEMSET(dest, (NXGL_PIXEL_T)color, lnlen);
}
#else
/* Then draw the run from (line + ix1) to (line + ix2) */
dest = line + NXGL_SCALEX(ix1);
NXGL_MEMSET(dest, (NXGL_PIXEL_T)color, width);
#endif
}
/* Move to the start of the next line */
line += stride;
/* Add the dx/dy value to get the run positions on the next row */
x1 += dx1dy;
x2 += dx2dy;
}
}
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