/*-------------------------------------------------------------------------
 * drawElements Image Library
 * --------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * 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.
 *
 *//*!
 * \file
 * \brief Image library.
 *//*--------------------------------------------------------------------*/

#include "deImage.h"
#include "deMemory.h"
#include "deInt32.h"
#include "deMath.h"

static int deImageFormat_getBytesPerPixel (deImageFormat format)
{
	DE_ASSERT(format == DE_IMAGEFORMAT_XRGB8888 || format == DE_IMAGEFORMAT_ARGB8888);
	DE_UNREF(format);
	return 4;
}

static void* getPixelAddress (const deImage* image, int x, int y)
{
	int offset = ((y*image->width) + x) * deImageFormat_getBytesPerPixel(image->format);
	DE_ASSERT(deInBounds32(x, 0, image->width));
	DE_ASSERT(deInBounds32(y, 0, image->height));
	return (void*)((deUint8*)image->pixels + offset);
}

deImage* deImage_create (int width, int height, deImageFormat format)
{
	deImage*	image	= DE_NEW(deImage);
	int			bpp		= deImageFormat_getBytesPerPixel(format);
	if (!image)
		return DE_NULL;

	image->width	= width;
	image->height	= height;
	image->format	= format;
	image->pixels	= deMalloc(width * height * bpp);
	if (!image->pixels)
	{
		deFree(image);
		return DE_NULL;
	}
	memset(image->pixels, 0, width * height * bpp);

	return image;
}

void deImage_destroy (deImage* image)
{
	deFree(image->pixels);
	deFree(image);
}

deARGB deImage_getPixel (const deImage* image, int x, int y)
{
	void* addr = getPixelAddress(image, x, y);
	switch (image->format)
	{
		case DE_IMAGEFORMAT_XRGB8888:	return *(deARGB*)addr;
		case DE_IMAGEFORMAT_ARGB8888:	return *(deARGB*)addr;
		default:
			DE_FATAL("deImage_getPixel(): invalid format");
			return deARGB_black();
	}
}

void deImage_setPixel (deImage* image, int x, int y, deARGB argb)
{
	void* addr = getPixelAddress(image, x, y);
	switch (image->format)
	{
		case DE_IMAGEFORMAT_XRGB8888:	*(deARGB*)addr = argb;	break;
		case DE_IMAGEFORMAT_ARGB8888:	*(deARGB*)addr = argb;	break;
		default:
			DE_FATAL("deImage_getPixel(): invalid format");
	}
}

deImage* deImage_convertFormat (const deImage* image, deImageFormat format)
{
	int			width		= image->width;
	int			height		= image->height;
	deImage*	converted	= deImage_create(width, height, format);
	if (!converted)
		return DE_NULL;

	if (format == image->format)
		memcpy(converted->pixels, image->pixels, width * height * deImageFormat_getBytesPerPixel(format));
	else
	{
		int x, y;
		for (y = 0; y < height; y++)
			for (x = 0; x < width; x++)
				deImage_setPixel(converted, x, y, deImage_getPixel(image, x, y));
	}

	return converted;
}

deImage* deImage_scale (const deImage* srcImage, int dstWidth, int dstHeight)
{
	int			srcWidth	= srcImage->width;
	int			srcHeight	= srcImage->height;
	deImage*	result		= deImage_create(dstWidth, dstHeight, srcImage->format);
	int			x, y;

	for (y = 0; y < dstHeight; y++)
	{
		for (x = 0; x < dstWidth; x++)
		{
			float	xFloat	= ((float)x + 0.5f) / (float)dstWidth * (float)srcImage->width - 0.5f;
			float	yFloat	= ((float)y + 0.5f) / (float)dstHeight * (float)srcImage->height - 0.5f;
			int		xFixed	= deFloorFloatToInt32(xFloat * 256.0f);
			int		yFixed	= deFloorFloatToInt32(yFloat * 256.0f);
			int		xFactor	= (xFixed & 0xFF);
			int		yFactor	= (yFixed & 0xFF);
			int		f00		= ((256-xFactor) * (256-yFactor)) >> 8;
			int		f10		= ((256-xFactor) * yFactor) >> 8;
			int		f01		= (xFactor * (256-yFactor)) >> 8;
			int		f11		= (xFactor * yFactor) >> 8;
			int		x0		= (xFixed >> 8);
			int		y0		= (yFixed >> 8);
			int		x1		= deClamp32(x0+1, 0, srcWidth-1);
			int		y1		= deClamp32(y0+1, 0, srcHeight-1);
			DE_ASSERT(deInBounds32(x0, 0, srcWidth));
			DE_ASSERT(deInBounds32(y0, 0, srcHeight));

			/* Filtering. */
			{
				deARGB p00 = deImage_getPixel(srcImage, x0, y0);
				deARGB p10 = deImage_getPixel(srcImage, x1, y0);
				deARGB p01 = deImage_getPixel(srcImage, x0, y1);
				deARGB p11 = deImage_getPixel(srcImage, x1, y1);
				deARGB pix = deARGB_add(deARGB_add(deARGB_multiply(p00, f00), deARGB_multiply(p10, f10)),
										deARGB_add(deARGB_multiply(p01, f01), deARGB_multiply(p11, f11)));
				deImage_setPixel(result, x, y, pix);
			}
		}
	}

	return result;
}

void deImage_copyToUint8RGBA (const deImage* image, deUint8* pixels)
{
	int width	= image->width;
	int height	= image->height;
	int x,y;

	for (y = 0; y < height; y++)
	for (x = 0; x < width; x++)
	{
		deARGB	pixel	= deImage_getPixel(image, x, y);
		int		ndx		= (y * width) + x;
		pixels[4*ndx+0] = (deUint8)deARGB_getRed(pixel);
		pixels[4*ndx+1] = (deUint8)deARGB_getGreen(pixel);
		pixels[4*ndx+2] = (deUint8)deARGB_getBlue(pixel);
		pixels[4*ndx+3] = (deUint8)deARGB_getAlpha(pixel);
	}
}

void* deImage_getPixelPtr (const deImage* image)
{
	return image->pixels;
}

int deImage_getWidth (const deImage* image)
{
	return image->width;
}

int deImage_getHeight (const deImage* image)
{
	return image->height;
}