FreeRDP/libfreerdp/gdi/clipping.c

/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * GDI Clipping Functions
 *
 * Copyright 2010-2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
 * Copyright 2016 Armin Novak <armin.novak@thincast.com>
 * Copyright 2016 Thincast Technologies GmbH
 *
 * Licensed 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <freerdp/freerdp.h>
#include <freerdp/gdi/gdi.h>

#include <freerdp/gdi/region.h>

#include "clipping.h"

BOOL gdi_SetClipRgn(HGDI_DC hdc, INT32 nXLeft, INT32 nYLeft, INT32 nWidth, INT32 nHeight)
{
	return gdi_SetRgn(hdc->clip, nXLeft, nYLeft, nWidth, nHeight);
}

/**
 * Get the current clipping region.\n
 * @msdn{dd144866}
 * @param hdc device context
 * @return clipping region
 */

HGDI_RGN gdi_GetClipRgn(HGDI_DC hdc)
{
	return hdc->clip;
}

/**
 * Set the current clipping region to null.
 * @param hdc device context
 * @return nonzero on success, 0 otherwise
 */

BOOL gdi_SetNullClipRgn(HGDI_DC hdc)
{
	gdi_SetClipRgn(hdc, 0, 0, 0, 0);
	hdc->clip->null = TRUE;
	return TRUE;
}

/**
 * Clip coordinates according to clipping region
 * @param hdc device context
 * @param x x1
 * @param y y1
 * @param w width
 * @param h height
 * @param srcx source x1
 * @param srcy source y1
 * @return nonzero if there is something to draw, 0 otherwise
 */

BOOL gdi_ClipCoords(HGDI_DC hdc, INT32* x, INT32* y, INT32* w, INT32* h, INT32* srcx, INT32* srcy)
{
	GDI_RECT bmp;
	GDI_RECT clip;
	GDI_RECT coords;
	HGDI_BITMAP hBmp;
	int dx = 0;
	int dy = 0;
	BOOL draw = TRUE;

	if (hdc == NULL)
		return FALSE;

	hBmp = (HGDI_BITMAP)hdc->selectedObject;

	if (hBmp != NULL)
	{
		if (hdc->clip->null)
		{
			gdi_CRgnToRect(0, 0, hBmp->width, hBmp->height, &clip);
		}
		else
		{
			gdi_RgnToRect(hdc->clip, &clip);
			gdi_CRgnToRect(0, 0, hBmp->width, hBmp->height, &bmp);

			if (clip.left < bmp.left)
				clip.left = bmp.left;

			if (clip.right > bmp.right)
				clip.right = bmp.right;

			if (clip.top < bmp.top)
				clip.top = bmp.top;

			if (clip.bottom > bmp.bottom)
				clip.bottom = bmp.bottom;
		}
	}
	else
	{
		gdi_RgnToRect(hdc->clip, &clip);
	}

	gdi_CRgnToRect(*x, *y, *w, *h, &coords);

	if (coords.right >= clip.left && coords.left <= clip.right && coords.bottom >= clip.top &&
	    coords.top <= clip.bottom)
	{
		/* coordinates overlap with clipping region */
		if (coords.left < clip.left)
		{
			dx = (clip.left - coords.left);
			coords.left = clip.left;
		}

		if (coords.right > clip.right)
			coords.right = clip.right;

		if (coords.top < clip.top)
		{
			dy = (clip.top - coords.top);
			coords.top = clip.top;
		}

		if (coords.bottom > clip.bottom)
			coords.bottom = clip.bottom;
	}
	else
	{
		/* coordinates do not overlap with clipping region */
		coords.left = 0;
		coords.right = 0;
		coords.top = 0;
		coords.bottom = 0;
		draw = FALSE;
	}

	if (srcx != NULL)
		*srcx += dx;

	if (srcy != NULL)
		*srcy += dy;

	gdi_RectToCRgn(&coords, x, y, w, h);
	return draw;
}