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incubator-nuttx/graphics/nxbe/nxbe_clipper.c

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/****************************************************************************
* graphics/nxbe/nxbe_clipper.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 <stdbool.h>
#include <stdlib.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/nx/nxglib.h>
#include "nxbe.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define NX_INITIAL_STACKSIZE (32)
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure is a container that retains an associated between a
* window instance and a rectangle.
*/
struct nxbe_cliprect_s
{
FAR struct nxbe_window_s *wnd;
struct nxgl_rect_s rect;
};
/* This is the stack of pending clip operations */
struct nxbe_clipstack_s
{
uint16_t npushed; /* Number of deferred rectangles in stack */
uint16_t mxrects; /* The capacity of the stack */
struct nxbe_cliprect_s *stack; /* The stack of deferred rectangles */
};
/****************************************************************************
* Private Data
****************************************************************************/
static const uint8_t g_nxcliporder[4][4] =
{
{ NX_TOP_NDX, NX_LEFT_NDX, NX_RIGHT_NDX, NX_BOTTOM_NDX }, /* index = NX_CLIPORDER_TLRB */
{ NX_TOP_NDX, NX_RIGHT_NDX, NX_LEFT_NDX, NX_BOTTOM_NDX }, /* NX_CLIPORDER_TRLB */
{ NX_BOTTOM_NDX, NX_LEFT_NDX, NX_RIGHT_NDX, NX_TOP_NDX }, /* NX_CLIPORDER_BLRT */
{ NX_BOTTOM_NDX, NX_RIGHT_NDX, NX_LEFT_NDX, NX_TOP_NDX }, /* NX_CLIPORDER_BRLT */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxbe_pushrectangle
****************************************************************************/
static inline void nxbe_pushrectangle(FAR struct nxbe_clipstack_s *stack,
FAR struct nxbe_window_s *wnd,
FAR const struct nxgl_rect_s *rect)
{
/* Check if there is room on the stack to hold another rectangle */
if ((stack->npushed + 1) > stack->mxrects)
{
/* No then we will need to reallocate the stack to hold more */
int mxrects = stack->mxrects ? 2 *
stack->mxrects : NX_INITIAL_STACKSIZE;
struct nxbe_cliprect_s *newstack;
newstack = kmm_realloc(stack->stack,
sizeof(struct nxbe_cliprect_s) * mxrects);
if (!newstack)
{
gerr("ERROR: Failed to reallocate stack\n");
return;
}
stack->stack = newstack;
stack->mxrects = mxrects;
}
/* Then push the new rectangle onto the stack */
stack->stack[stack->npushed].wnd = wnd;
nxgl_rectcopy(&stack->stack[stack->npushed].rect, rect);
stack->npushed++;
}
/****************************************************************************
* Name: nxbe_poprectangle
****************************************************************************/
static inline bool nxbe_poprectangle(struct nxbe_clipstack_s *stack,
FAR struct nxbe_window_s **wnd,
struct nxgl_rect_s *rect)
{
if (stack->npushed > 0)
{
stack->npushed--;
*wnd = stack->stack[stack->npushed].wnd;
nxgl_rectcopy(rect, &stack->stack[stack->npushed].rect);
return true;
}
return false;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxbe_clipper
*
* Description:
* Perform flexible clipping operations. Callbacks are executed for
* each oscured and visible portions of the window.
*
* Input Parameters:
* wnd - The window to be clipped.
* rect - The region of concern within the window
* order - Specifies the order to process the parts of the
* non-intersecting sub-rectangles.
* cops - The callbacks to handle obscured and visible parts of the
* sub-rectangles.
* plane - The raster operations to be used by the callback functions.
* These may vary with different color formats.
*
* Returned Value:
* None
*
****************************************************************************/
void nxbe_clipper(FAR struct nxbe_window_s *wnd,
FAR const struct nxgl_rect_s *dest, uint8_t order,
FAR struct nxbe_clipops_s *cops,
FAR struct nxbe_plane_s *plane)
{
struct nxbe_clipstack_s stack;
FAR struct nxbe_window_s *currw;
struct nxgl_rect_s rect;
struct nxgl_rect_s obscuredrect;
struct nxgl_rect_s currbounds;
struct nxgl_rect_s nonoverlapped[4];
int i;
/* Initialize the stack where we will keep deferred rectangle operations */
stack.npushed = 0;
stack.mxrects = 0;
stack.stack = NULL;
/* Loop until there are no further pending operations */
nxgl_rectcopy(&rect, dest); /* Start with the whole dest rectangle */
do
{
/* Loop for every window from the current window and above.
* Only windows above the current window can obscure the current window
*/
for (currw = wnd; currw; currw = currw->above)
{
/* Does the current window overlap the dest rectangle? */
currbounds = currw->bounds;
if (nxgl_rectoverlap(&rect, &currbounds))
{
/* Yes.. then it obscures all or part of the dest rectangle.
* Divide the potentially visible, non-overlapping regions into
* 4 smaller rectangles and push them onto the stack for
* processing on the next time through the outer loop.
*/
nxgl_nonintersecting(nonoverlapped, &rect, &currbounds);
for (i = 3; i >= 0; i--)
{
/* Push the rectangles in the order specific by the input
* argument of that name.
*/
struct nxgl_rect_s *candidate =
&nonoverlapped[g_nxcliporder[order][i]];
if (!nxgl_nullrect(candidate))
{
nxbe_pushrectangle(&stack, currw->above, candidate);
}
}
/* Now performed any required processing on the obscurred,
* overlapped region.
*/
nxgl_rectintersect(&obscuredrect, &rect, &currbounds);
cops->obscured(cops, plane, &obscuredrect);
/* Break out of the loop to process the pushed rectangles */
break;
}
}
/* If there are no other windows overlapping this rectangle, then this
* rectangular region must be visible.
*/
if (!currw && !nxgl_nullrect(&rect))
{
cops->visible(cops, plane, &rect);
}
}
while (nxbe_poprectangle(&stack, &wnd, &rect));
/* Done! If any stack was allocated, then free it before exit-ting */
if (stack.stack)
{
kmm_free(stack.stack);
}
}
/****************************************************************************
* Name: nxbe_clipnull
*
* Description:
* The do-nothing clipping callback function
*
****************************************************************************/
void nxbe_clipnull(FAR struct nxbe_clipops_s *cops,
FAR struct nxbe_plane_s *plane,
FAR const struct nxgl_rect_s *rect)
{
}
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