dip.c

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				*dest=rb;
				dest[1]=gb;
				dest[2]=bb;
			}
		}
		dest+=3;
	}
}

/* src is a block of four-bytes RGBA. All bytes are gamma corrected. length is
 * number of pixels. output is input powered to the given gamma, passed into
 * dest. src and dest may be identical and it will work. rb, gb, bb are 0-65535
 * in linear monitor output photon space. alpha 255 means full image no background.
 * We assume unsigned short holds at least 16 bits. */
void apply_gamma_exponent_and_undercolor_64_to_48_table(unsigned short *dest
		,unsigned short *src, int lenght, unsigned short *gamma_table
		,unsigned short rb, unsigned short gb, unsigned short bb)
{
	unsigned alpha, calpha;
	unsigned short ri,gi,bi;

	for (;lenght;lenght--)
	{
		ri=gamma_table[*src];
		gi=gamma_table[src[1]+65536];
		bi=gamma_table[src[2]+131072];
		alpha=src[3];
		src+=4;
		if (((alpha+1)&0xffff)>=2){
			calpha=65535-alpha;
			*dest=(ri*alpha+calpha*rb+32767)/65535;
			dest[1]=(gi*alpha+calpha*gb+32767)/65535;
			dest[2]=(bi*alpha+calpha*bb+32767)/65535;
		}else{
			if (alpha){
				*dest=ri;
				dest[1]=gi;
				dest[2]=bi;
			}else{
				*dest=rb;
				dest[1]=gb;
				dest[2]=bb;
			}
		}
		dest+=3;
	}
}

/* src is a block of three-bytes. All bytes are gamma corrected. length is
 * number of triplets. output is input powered to the given gamma, passed into
 * dest. src and dest may be identical and it will work.
 * We assume unsigned short holds at least 16 bits. */
void apply_gamma_exponent_48_to_48(unsigned short *dest,
		unsigned short *src, int lenght, float red_gamma
		,float green_gamma, float blue_gamma)
{
	float a, inv_65535=1/((float)65535);

	for (;lenght;lenght--,src+=3,dest+=3)
	{
		a=*src;
		a*=inv_65535;
		a=pow(a,red_gamma);
		*dest=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (*dest>=0x10000) *dest=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		a=src[1];
		a*=inv_65535;
		a=pow(a,green_gamma);
		dest[1]=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (dest[1]>=0x10000) dest[1]=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		a=src[2];
		a*=inv_65535;
		a=pow(a,blue_gamma);
		dest[2]=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (dest[2]>=0x10000) dest[2]=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
	}
}

/* src is a block of three-bytes. All bytes are gamma corrected. length is
 * number of triples. output is input powered to the given gamma, passed into
 * dest. src and dest may be identical and it will work.
 * We assume unsigned short holds at least 16 bits. */
void apply_gamma_exponent_48_to_48_table(unsigned short *dest,
		unsigned short *src, int lenght, unsigned short *table)
{
	for (;lenght;lenght--,src+=3,dest+=3)
	{
		*dest=table[*src];
		dest[1]=table[src[1]+65536];
		dest[2]=table[src[2]+131072];
	}
}

/* src is a block of three-bytes. All bytes are gamma corrected. length is
 * number of triples. output is input powered to the given gamma, passed into
 * dest. src and dest may be identical and it will work.
 * We assume unsigned short holds at least 16 bits. */
void apply_gamma_exponent_24_to_48(unsigned short *dest, unsigned char *src, int
			  lenght, float red_gamma, float green_gamma, float
			  blue_gamma)
{
	float a;
	float inv_255=1/((float)255);
	
	for (;lenght;lenght--,src+=3,dest+=3)
	{
		a=*src;
		a*=inv_255;
		a=pow(a,red_gamma);
		*dest=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (*dest>=0x10000) *dest=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		a=src[1];
		a*=inv_255;
		a=pow(a,green_gamma);
		dest[1]=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (dest[1]>=0x10000) dest[1]=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		a=src[2];
		a*=inv_255;
		a=pow(a,blue_gamma);
		dest[2]=(a*65535)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		if (dest[2]>=0x10000) dest[2]=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
	}
}

/* Allocates new gamma_table and fills it with mapping 8 bits ->
 * power to user_gamma/cimg->*_gamma -> 16 bits 
 * We assume unsigned short holds at least 16 bits. */
void make_gamma_table(struct cached_image *cimg)
{
	double rg=user_gamma/cimg->red_gamma;
	double gg=user_gamma/cimg->green_gamma;
	double bg=user_gamma/cimg->blue_gamma;
	double inv;
	int a;
	unsigned short *ptr_16;

	if (cimg->buffer_bytes_per_pixel<=4){
		/* 8-bit */
		inv=1/((double)255);
		ptr_16=mem_alloc(768*sizeof(*(cimg->gamma_table)));
		cimg->gamma_table=ptr_16;
		for (a=0;a<256;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,rg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
		/* To test against crappy arithmetics */
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
		for (a=0;a<256;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,gg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
		for (a=0;a<256;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,bg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
	}else{
		/* 16-bit */
		inv=1/((double)65535);
		ptr_16=mem_alloc(196608*sizeof(*(cimg->gamma_table)));
		cimg->gamma_table=ptr_16;
		for (a=0;a<0x10000;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,rg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
		for (a=0;a<0x10000;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,gg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
		for (a=0;a<0x10000;a++,ptr_16++){
			*ptr_16=65535*pow(((double)a)*inv,bg)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (*ptr_16>=0x10000) *ptr_16=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
		}
	}
}

/* We assume unsigned short holds at least 16 bits. */
void apply_gamma_exponent_24_to_48_table(unsigned short *dest, unsigned char *src, int
			  lenght, unsigned short *table)
{
	for (;lenght;lenght--,src+=3,dest+=3)
	{
		dest[0]=table[src[0]];
		dest[1]=table[src[1]+256];
		dest[2]=table[src[2]+512];
	}
}

/* Input is 0-255 (8-bit). Output is 0-255 (8-bit)*/
unsigned char apply_gamma_single_8_to_8(unsigned char input, float gamma)
{
	return 255*pow(((float) input)/255,gamma)+0.5;
}

/* Input is 0-255 (8-bit). Output is 0-65535 (16-bit)*/
/* We assume unsigned short holds at least 16 bits. */
unsigned short apply_gamma_single_8_to_16(unsigned char input, float gamma)
{
	float a=input;
	unsigned short retval;

	a/=255;
	a=pow(a,gamma);
	a*=65535;
	retval = a+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (retval>=0x10000) retval=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
	return retval;
}

/* Input is 0-65535 (16-bit). Output is 0-255 (8-bit)*/
/* We assume unsigned short holds at least 16 bits. */
unsigned char apply_gamma_single_16_to_8(unsigned short input, float gamma)
{
	return pow(((float)input)/65535,gamma)*255+0.5;
}

/* Input is 0-65535 (16-bit). Output is 0-255 (8-bit)*/
unsigned short apply_gamma_single_16_to_16(unsigned short input, float gamma)
{
	unsigned short retval;
	
	retval = 65535*pow(((float)input)/65535,gamma)+0.5;
#if SIZEOF_UNSIGNED_SHORT > 2
			if (retval>=0x10000) retval=0xffff;
#endif /* #if SIZEOF_UNSIGNED_SHORT > 2 */
	return retval;
}

/* Points to the next unread byte from png data block */
extern unsigned char font_data[];
extern struct letter letter_data[];
extern struct font font_table[];
extern int n_fonts; /* Number of fonts. font number 0 is system_font (it's
		     * images are in system_font/ directory) and is used
		     * for special purpose.
		     */

/* Returns a pointer to a structure describing the letter found or NULL
 * if the letter is not found. Tries all possibilities in the style table
 * before returning NULL.
 */
struct letter *find_stored_letter(int *style_table, int letter_number)
{
	int first, last, half, diff, font_index, font_number;

	for (font_index=n_fonts-1;font_index;font_index--)
	{
		font_number=*style_table++;

		first=font_table[font_number].begin;
		last=font_table[font_number].length+first-1;

		while(first<=last){
			half=(first+last)>>1;
			diff=letter_data[half].code-letter_number;
			if (diff>=0){
				if (diff==0){
					return letter_data+half;
				}else{
					/* Value in table is bigger */
					last=half-1;
				}
			}else{
				/* Value in the table is smaller */
				first=half+1;
			}
		}
	}
	
	/* 0 is system font, 0 is blotch char. This must be present
	 * or we segfault :) */
#ifdef REPORT_UNKNOWN
	fprintf(stderr,"letter 0x%04x not found\n",letter_number);
#endif /* #ifdef REPORT_UNKNOWN */
	return letter_data+font_table[0].begin;
}

void read_stored_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
{
	struct read_work *work;

	work=png_get_io_ptr(png_ptr);
	if (length>(png_uint_32)work->length) png_error(png_ptr,"Ran out of input data");
	memcpy(data,work->pointer,length);
	work->length-=length;
	work->pointer+=length;
}

void my_png_warning(png_structp a, png_const_charp b)
{
}

void my_png_error(png_structp a, png_const_charp error_string)
{
	error("Error when loading compiled-in font: %s.",error_string);
}

/* Loads width and height of the PNG (nothing is scaled). Style table is
 * already incremented.
 */
inline static void load_metric(int *x, int *y, int char_number, int *style_table)
{
	struct letter *l;

	l=find_stored_letter(style_table,char_number);
	if (!l){
		*x=0;
		*y=0;
	}else{
		*x=l->xsize;
		*y=l->ysize;
	}
	return;
}

/* The data tha fall out of this function express this: 0 is paper. 255 is ink. 34
 * is 34/255ink+(255-34)paper. No gamma is involved in this formula, as you can see.
 * The multiplications and additions take place in photon space.
 */
static void load_char(unsigned char **dest, int *x, int *y, 
unsigned char *png_data, int png_length, struct style *style)
{
	png_structp png_ptr;
	png_infop info_ptr;
	double gamma;
	int y1,number_of_passes;
	unsigned char **ptrs;
	struct read_work work;

	work.pointer = png_data;
	work.length = png_length;
	
	png_ptr=png_create_read_struct(PNG_LIBPNG_VER_STRING,
			NULL, my_png_error, my_png_warning);
	info_ptr=png_create_info_struct(png_ptr);
	png_set_read_fn(png_ptr,&work,(png_rw_ptr)&read_stored_data);
	png_read_info(png_ptr, info_ptr);
	*x=png_get_image_width(png_ptr,info_ptr);
	*y=png_get_image_height(png_ptr,info_ptr);
	if (png_get_gAMA(png_ptr,info_ptr, &gamma))
		png_set_gamma(png_ptr, 1.0, gamma);
	else
		png_set_gamma(png_ptr, 1.0, sRGB_gamma);
	{
		int bit_depth;
		int color_type;

		color_type=png_get_color_type(png_ptr, info_ptr);
		bit_depth=png_get_bit_depth(png_ptr, info_ptr);
		if (color_type==PNG_COLOR_TYPE_GRAY){
			if (bit_depth<8){
				 png_set_expand(png_ptr);
			}
			if (bit_depth==16){
				 png_set_strip_16(png_ptr);
			}
		}
		if (color_type==PNG_COLOR_TYPE_PALETTE){
			png_set_expand(png_ptr);
#ifdef HAVE_PNG_SET_RGB_TO_GRAY
			png_set_rgb_to_gray(png_ptr,1,54.0*256,183.0*256);
#else
			goto end;
#endif
		}
		if (color_type & PNG_COLOR_MASK_ALPHA){
			png_set_strip_alpha(png_ptr);
		}
		if (color_type==PNG_COLOR_TYPE_RGB ||
			color_type==PNG_COLOR_TYPE_RGB_ALPHA){
#ifdef HAVE_PNG_SET_RGB_TO_GRAY
			png_set_rgb_to_gray(png_ptr, 1, 54.0*256, 183.0*256);
#else
			goto end;
#endif
		}
		
	}
	/* If the depth is different from 8 bits/gray, make the libpng expand
	 * it to 8 bit gray.
	 */
	number_of_passes=png_set_interlace_handling(png_ptr);
	png_read_update_info(png_ptr,info_ptr);
	if (*x && (unsigned)*x * (unsigned)*y / (unsigned)*x != (unsigned)*y) overalloc();
	if ((unsigned)*x * (unsigned)*y > MAXINT) overalloc();
	*dest=mem_alloc(*x*(*y));
	if ((unsigned)*y > MAXINT / sizeof(*ptrs)) overalloc();
	ptrs=mem_alloc(*y*sizeof(*ptrs));
	for (y1=0;y1<*y;y1++) ptrs[y1]=*dest+*x*y1;
	for (;number_of_passes;number_of_passes--){
		png_read_rows(png_ptr, ptrs, NULL, *y);
	}
	png_read_end(png_ptr, NULL);
	png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
	mem_free(ptrs);
	return;
#ifndef HAVE_PNG_SET_RGB_TO_GRAY
	end:
	if (*x && (unsigned)*x * (unsigned)*y / (unsigned)*x != (unsigned)*y) overalloc();
	if ((unsigned)*x * (unsigned)*y > MAXINT) overalloc();
	*dest=mem_calloc(*x*(*y));
	return;
#endif
}

/* Like load_char, but we dictate the y.
 */
static void load_scaled_char(void **dest, int *x, int y,
unsigned char *png_data, int png_length, struct style *style)
{
	unsigned char *interm;
	unsigned char *interm2;
	unsigned char *i2ptr,*dptr;
	int ix, iy, y0, x0, c;
	float conv0, conv1,sharpness,contrast;

	load_char(&interm, &ix,&iy,png_data, png_length,style);
	if (style->mono_space>=0)
		*x=compute_width(style->mono_space, style->mono_height, y);
	else
		*x=compute_width(ix,iy,y);
	if (display_optimize) *x*=3;
	scale_gray(interm, ix,iy, (unsigned char **)dest, *x, y);
	if (y>32||y<=0) return ; /* No convolution */
	ix=*x+2; /* There is one-pixel border around */
	iy=y+2;
	if (ix && (unsigned)ix * (unsigned)iy / (unsigned)ix != (unsigned)iy) overalloc();
	if ((unsigned)ix * (unsigned)iy > MAXINT) overalloc();
	interm2=mem_alloc(ix*iy);
	i2ptr=interm2+ix+1;
	dptr=*dest;
	memset(interm2,0,ix);
	memset(interm2+(iy-1)*ix,0,ix);
	for (y0=y;y0;y0--){
		i2ptr[-1]=0;
		memcpy(i2ptr,dptr,*x);
		i2ptr[ix-1]=0;
		i2ptr+=ix;
		dptr+=*x;
	}
	i2ptr=interm2+ix+1;
	dptr=*dest;

	/* Determine the sharpness and contrast */
	sharpness=fancy_constants[2*y-2];
	contrast=fancy_constants[2*y-1];

	/* Compute the matrix constants from contrast and sharpness */
	conv0=(1+sharpness)*contrast;
	conv1=-sharpness*0.25*contrast;
	
	for (y0=y;y0;y0--){
		for (x0=*x;x0;x0--){
			/* Convolution */
			c=((*i2ptr)*conv0)+i2ptr[-ix]*conv1+i2ptr[-1]*conv1+i2ptr[1]*conv1+i2ptr[ix]*conv1+0.5;
			if (((unsigned)c)>=256) c=c<0?0:255;
			*dptr=c;
			dptr++;
			i2ptr++;
		}
		i2ptr+=2;
	}
	mem_free(interm2);
}

/* Adds required entry into font_cache and returns pointer to the entry.
 * We assume the entry is FC_COLOR.
 */
struct font_cache_entry *supply_color_cache_entry (struct graphics_driver
*gd, struct style *style, struct letter *letter)
{
	struct font_cache_entry *found, *new;
	unsigned short *primary_data;
	int do_free=0;
	struct font_cache_entry template;
	unsigned short red, green, blue;
	unsigned bytes_consumed;

	template.bitmap.y=style->height;
	template.type=FC_BW;
	/* The BW entries will be added only for background images which
	 * are not yet implemented, but will be in the future.
	 */

	found=lru_lookup(&font_cache, &template, letter->bw_list);
	if (!found){
		found=mem_alloc(sizeof(*found));
		found->bitmap.y=style->height;
		load_scaled_char(&(found->bitmap.data),&(found->bitmap.x),
			found->bitmap.y, font_data+letter->begin,
			letter->length, style);
		do_free=1;
	}
	new=mem_alloc(sizeof(*new));
	new->type=FC_COLOR;
	new->bitmap=found->bitmap;
	new->r0=style->r0;
	new->g0=style->g0;
	new->b0=style->b0;
	new->r1=style->r1;
	new->g1=style->g1;
	new->b1=style->b1;
	new->mono_space=style->mono_space;
	new->mono_height=style->mono_height;

	if (new->bitmap.x && (unsigned)new->bitmap.x * (unsigned)new->bitmap.y / (unsigned)new->bitmap.x != (unsigned)new->bitmap.y) overalloc();
	if ((unsigned)new->bitmap.x * (unsigned)new->bitmap.y > MAXINT / 3 / sizeof(*primary_data)) overalloc();
	primary_data=mem_alloc(3
			*new->bitmap.x*new->bitmap.y*sizeof(*primary_data));

	/* We assume the gamma of HTML styles is in sRGB space */
	round_color_sRGB_to_48(&red, &green, &blue,
		((style->r0)<<16)|((style->g0)<<8)|(style->b0));
	mix_two_colors(primary_data, found->bitmap.data,
		found->bitmap.x*found->bitmap.y,
		red,green,blue,