incubator-nuttx/graphics/nxglib/pwfb/pwfb_filltrapezoid.c

294 lines
7.7 KiB
C

/****************************************************************************
* graphics/nxglib/pwfb/pwfb_filltrapezoid.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <fixedmath.h>
#include <nuttx/nx/nxglib.h>
#include <nuttx/nx/nxbe.h>
#include "nxglib_bitblit.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Make sure that this file is used in the proper context */
#ifndef NXGLIB_SUFFIX
# error "NXGLIB_SUFFIX must be defined before including this header file"
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pwfb_filltrapezoid*bpp
*
* Description:
* 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(pwfb_filltrapezoid, NXGLIB_SUFFIX)
(
FAR struct nxbe_window_s *bwnd,
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 = bwnd->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 = (FAR uint8_t *)bwnd->fbmem + y1 * stride ;
/* Then fill the trapezoid line-by-line */
while (nrows--)
{
#ifdef CONFIG_NX_ANTIALIASING
b16_t frac;
#endif
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 /* NXGLIB_BITSPERPIXEL < 8 */
/* Then draw the run from (line + ix1) to (line + ix2) */
dest = line + NXGL_SCALEX(ix1);
#ifdef CONFIG_NX_ANTIALIASING
/* Perform blending on the first pixel of the row */
frac = b16ONE - b16frac(x1);
NXGL_BLEND(dest, (NXGL_PIXEL_T)color, frac);
dest += NXGL_SCALEX(1);
width--;
if (width > 0)
{
/* Copy pixels between the first and last pixel of the row. */
if (width > 1)
{
NXGL_MEMSET(dest, (NXGL_PIXEL_T)color, width - 1);
}
/* And blend the final pixel */
dest += NXGL_SCALEX(width - 1);
frac = b16frac(x2);
NXGL_BLEND(dest, (NXGL_PIXEL_T)color, frac);
}
#else /* CONFIG_NX_ANTIALIASING */
NXGL_MEMSET(dest, (NXGL_PIXEL_T)color, width);
#endif /* CONFIG_NX_ANTIALIASING */
#endif /* NXGLIB_BITSPERPIXEL < 8 */
}
/* 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;
}
}