/*
*********************************************************************
* File: ximawmf.h
* Purpose: Windows Metafile Class Loader and Writer
* Author: Volker Horch - vhorch@gmx.de
* created: 13-Jun-2002
*********************************************************************
*/
/*
*********************************************************************
Notes by Author:
*********************************************************************
Limitations:
============
a) Transparency:
A Metafile is vector graphics, which has transparency by design.
This class always converts into a Bitmap format. Transparency is
supported, but there is no good way to find out, which parts
of the Metafile are transparent. There are two ways how we can
handle this:
- Clear the Background of the Bitmap with the background color
you like (i have used COLOR_WINDOW) and don't support transparency.
below #define XMF_SUPPORT_TRANSPARENCY 0
#define XMF_COLOR_BACK RGB(Background color you like)
- Clear the Background of the Bitmap with a very unusual color
(which one ?) and use this color as the transparent color
below #define XMF_SUPPORT_TRANSPARENCY 1
#define XMF_COLOR_TRANSPARENT_R ...
#define XMF_COLOR_TRANSPARENT_G ...
#define XMF_COLOR_TRANSPARENT_B ...
b) Resolution
Once we have converted the Metafile into a Bitmap and we zoom in
or out, the image may not look very good. If we still had the
original Metafile, zooming would produce good results always.
c) Size
Although the filesize of a Metafile may be very small, it might
produce a Bitmap with a bombastic size. Assume you have a Metafile
with an image size of 6000*4000, which contains just one Metafile
record ((e.g. a line from (0,0) to (6000, 4000)). The filesize
of this Metafile would be let's say 100kB. If we convert it to
a 6000*4000 Bitmap with 24 Bits/Pixes, the Bitmap would consume
about 68MB of memory.
I have choosen, to limit the size of the Bitmap to max.
screensize, to avoid memory problems.
If you want something else,
modify #define XMF_MAXSIZE_CX / XMF_MAXSIZE_CY below
*********************************************************************
*/
#ifndef _XIMAWMF_H
#define _XIMAWMF_H
#include "ximage.h"
#if CXIMAGE_SUPPORT_WMF && CXIMAGE_SUPPORT_WINDOWS
class CxImageWMF: public CxImage
{
#pragma pack(1)
typedef struct tagRECT16
{
short int left;
short int top;
short int right;
short int bottom;
} RECT16;
// taken from Windos 3.11 SDK Documentation (Programmer's Reference Volume 4: Resources)
typedef struct tagMETAFILEHEADER
{
DWORD key; // always 0x9ac6cdd7
WORD reserved1; // reserved = 0
RECT16 bbox; // bounding rectangle in metafile units as defined in "inch"
WORD inch; // number of metafile units per inch (should be < 1440)
DWORD reserved2; // reserved = 0
WORD checksum; // sum of the first 10 WORDS (using XOR operator)
} METAFILEHEADER;
#pragma pack()
public:
CxImageWMF(): CxImage(CXIMAGE_FORMAT_WMF) { }
bool Encode(CxFile * hFile);
bool Encode(FILE *hFile) { CxIOFile file(hFile); return Encode(&file); }
bool Decode(CxFile * hFile, long nForceWidth=0, long nForceHeight=0);
bool Decode(FILE *hFile, long nForceWidth=0, long nForceHeight=0)
{ CxIOFile file(hFile); return Decode(&file,nForceWidth,nForceHeight); }
protected:
void ShrinkMetafile(int &cx, int &cy);
BOOL CheckMetafileHeader(METAFILEHEADER *pmetafileheader);
HENHMETAFILE ConvertWmfFiletoEmf(CxFile *pFile, METAFILEHEADER *pmetafileheader);
HENHMETAFILE ConvertEmfFiletoEmf(CxFile *pFile, ENHMETAHEADER *pemfh);
};
#define METAFILEKEY 0x9ac6cdd7L
// Background color definition (if no transparency). see Notes above
#define XMF_COLOR_BACK GetSysColor(COLOR_WINDOW)
// alternatives
//#define XMF_COLOR_BACK RGB(192, 192, 192) // lite gray
//#define XMF_COLOR_BACK RGB( 0, 0, 0) // black
//#define XMF_COLOR_BACK RGB(255, 255, 255) // white
// transparency support. see Notes above
#define XMF_SUPPORT_TRANSPARENCY 0
#define XMF_COLOR_TRANSPARENT_R 211
#define XMF_COLOR_TRANSPARENT_G 121
#define XMF_COLOR_TRANSPARENT_B 112
// don't change
#define XMF_COLOR_TRANSPARENT RGB (XMF_COLOR_TRANSPARENT_R, \
XMF_COLOR_TRANSPARENT_G, \
XMF_COLOR_TRANSPARENT_B)
// don't change
#define XMF_RGBQUAD_TRANSPARENT XMF_COLOR_TRANSPARENT_B, \
XMF_COLOR_TRANSPARENT_G, \
XMF_COLOR_TRANSPARENT_R, \
0
// max. size. see Notes above
// alternatives
//#define XMF_MAXSIZE_CX (GetSystemMetrics(SM_CXSCREEN)-10)
//#define XMF_MAXSIZE_CY (GetSystemMetrics(SM_CYSCREEN)-50)
//#define XMF_MAXSIZE_CX (2*GetSystemMetrics(SM_CXSCREEN)/3)
//#define XMF_MAXSIZE_CY (2*GetSystemMetrics(SM_CYSCREEN)/3)
#define XMF_MAXSIZE_CX 4000
#define XMF_MAXSIZE_CY 4000
#endif
#endif
Submit an article or tip