/src/FreeImage/Source/FreeImage/ConversionRGB16.cpp

  1// ==========================================================
  2// Bitmap conversion routines
  3//
  4// Design and implementation by
  5// - Hervé Drolon (drolon@infonie.fr)
  6//
  7// This file is part of FreeImage 3
  8//
  9// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
 10// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
 11// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
 12// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
 13// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
 14// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
 15// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
 16// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 17// THIS DISCLAIMER.
 18//
 19// Use at your own risk!
 20// ==========================================================
 21
 22#include "FreeImage.h"
 23#include "Utilities.h"
 24
 25// ----------------------------------------------------------
 26//   smart convert X to RGB16
 27// ----------------------------------------------------------
 28
 29FIBITMAP * DLL_CALLCONV
 30FreeImage_ConvertToRGB16(FIBITMAP *dib) {
 31	FIBITMAP *src = NULL;
 32	FIBITMAP *dst = NULL;
 33
 34	if(!FreeImage_HasPixels(dib)) return NULL;
 35
 36	const FREE_IMAGE_TYPE src_type = FreeImage_GetImageType(dib);
 37
 38	// check for allowed conversions 
 39	switch(src_type) {
 40		case FIT_BITMAP:
 41		{
 42			// convert to 24-bit if needed
 43			if((FreeImage_GetBPP(dib) == 24) || (FreeImage_GetBPP(dib) == 32)) {
 44				src = dib;
 45			} else {
 46				src = FreeImage_ConvertTo24Bits(dib);
 47				if(!src) return NULL;
 48			}
 49			break;
 50		}
 51		case FIT_UINT16:
 52			// allow conversion from unsigned 16-bit
 53			src = dib;
 54			break;
 55		case FIT_RGB16:
 56			// RGB16 type : clone the src
 57			return FreeImage_Clone(dib);
 58			break;
 59		case FIT_RGBA16:
 60			// allow conversion from 64-bit RGBA (ignore the alpha channel)
 61			src = dib;
 62			break;
 63		default:
 64			return NULL;
 65	}
 66
 67	// allocate dst image
 68
 69	const unsigned width = FreeImage_GetWidth(src);
 70	const unsigned height = FreeImage_GetHeight(src);
 71
 72	dst = FreeImage_AllocateT(FIT_RGB16, width, height);
 73	if(!dst) {
 74		if(src != dib) {
 75			FreeImage_Unload(src);
 76		}
 77		return NULL;
 78	}
 79
 80	// copy metadata from src to dst
 81	FreeImage_CloneMetadata(dst, src);
 82
 83	// convert from src type to RGB16
 84
 85	switch(src_type) {
 86		case FIT_BITMAP:
 87		{
 88			// Calculate the number of bytes per pixel (1 for 8-bit, 3 for 24-bit or 4 for 32-bit)
 89			const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
 90
 91			for(unsigned y = 0; y < height; y++) {
 92				const BYTE *src_bits = (BYTE*)FreeImage_GetScanLine(src, y);
 93				FIRGB16 *dst_bits = (FIRGB16*)FreeImage_GetScanLine(dst, y);
 94				for(unsigned x = 0; x < width; x++) {
 95					dst_bits[x].red   = src_bits[FI_RGBA_RED] << 8;
 96					dst_bits[x].green = src_bits[FI_RGBA_GREEN] << 8;
 97					dst_bits[x].blue  = src_bits[FI_RGBA_BLUE] << 8;
 98					src_bits += bytespp;
 99				}
100			}
101		}
102		break;
103
104		case FIT_UINT16:
105		{
106			for(unsigned y = 0; y < height; y++) {
107				const WORD *src_bits = (WORD*)FreeImage_GetScanLine(src, y);
108				FIRGB16 *dst_bits = (FIRGB16*)FreeImage_GetScanLine(dst, y);
109				for(unsigned x = 0; x < width; x++) {
110					// convert by copying greyscale channel to each R, G, B channels
111					dst_bits[x].red   = src_bits[x];
112					dst_bits[x].green = src_bits[x];
113					dst_bits[x].blue  = src_bits[x];
114				}
115			}
116		}
117		break;
118
119		case FIT_RGBA16:
120		{
121			for(unsigned y = 0; y < height; y++) {
122				const FIRGBA16 *src_bits = (FIRGBA16*)FreeImage_GetScanLine(src, y);
123				FIRGB16 *dst_bits = (FIRGB16*)FreeImage_GetScanLine(dst, y);
124				for(unsigned x = 0; x < width; x++) {
125					// convert and skip alpha channel
126					dst_bits[x].red   = src_bits[x].red;
127					dst_bits[x].green = src_bits[x].green;
128					dst_bits[x].blue  = src_bits[x].blue;
129				}
130			}
131		}
132		break;
133
134		default:
135			break;
136	}
137
138	if(src != dib) {
139		FreeImage_Unload(src);
140	}
141
142	return dst;
143}
144