/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 2010 Eli Gottlieb

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Eli Gottlieb
    eligottlieb@gmail.com
*/

#include <assert.h>
#include <X11/extensions/shape.h>
#include "SDL_x11shape.h"
#include "SDL_x11window.h"
#include "SDL_x11video.h"

SDL_WindowShaper* X11_CreateShaper(SDL_Window* window) {
	SDL_WindowShaper* result = NULL;
	if (SDL_X11_HAVE_XSHAPE) {  /* Make sure X server supports it. */
		result = malloc(sizeof(SDL_WindowShaper));
		result->window = window;
		result->alphacutoff = 0;
		result->usershownflag = 0;
		result->driverdata = malloc(sizeof(SDL_ShapeData));
		window->shaper = result;
		int resized_properly = X11_ResizeWindowShape(window);
		assert(resized_properly == 0);
	}

	return result;
}

int X11_ResizeWindowShape(SDL_Window* window) {
	SDL_ShapeData* data = window->shaper->driverdata;
	assert(data != NULL);
	
	unsigned int bitmapsize = window->w / 8;
	if(window->w % 8 > 0)
		bitmapsize += 1;
	bitmapsize *= window->h;
	if(data->bitmapsize != bitmapsize || data->bitmap == NULL) {
		data->bitmapsize = bitmapsize;
		if(data->bitmap != NULL)
			free(data->bitmap);
		data->bitmap = malloc(data->bitmapsize);
		if(data->bitmap == NULL) {
			SDL_SetError("Could not allocate memory for shaped-window bitmap.");
			return -1;
		}
	}
	
	window->shaper->usershownflag = window->flags & SDL_WINDOW_SHOWN;
	
	return 0;
}
	
int X11_SetWindowShape(SDL_WindowShaper *shaper,SDL_Surface *shape,SDL_WindowShapeMode *shapeMode) {
	if(shaper == NULL || shape == NULL || shaper->driverdata == NULL)
		return -1;
	if(!SDL_ISPIXELFORMAT_ALPHA(SDL_MasksToPixelFormatEnum(shape->format->BitsPerPixel,shape->format->Rmask,shape->format->Gmask,shape->format->Bmask,shape->format->Amask)))
		return -2;
	if(shape->w != shaper->window->w || shape->h != shaper->window->h)
		return -3;
	SDL_ShapeData *data = shaper->driverdata;
	
	/* Assume that shaper->alphacutoff already has a value, because SDL_SetWindowShape() should have given it one. */
	SDL_CalculateShapeBitmap(shaper->alphacutoff,shape,data->bitmap,8,1);
		
	SDL_WindowData *windowdata = (SDL_WindowData*)(shaper->window->driverdata);
	Pixmap shapemask = XCreateBitmapFromData(windowdata->videodata->display,windowdata->xwindow,data->bitmap,shaper->window->w,shaper->window->h);
	
	XShapeCombineMask(windowdata->videodata->display,windowdata->xwindow, ShapeBounding, 0, 0,shapemask, ShapeSet);
	XSync(windowdata->videodata->display,False);

	XFreePixmap(windowdata->videodata->display,shapemask);
	
	return 0;
}
