问题描述
是否有一种简便的方法来查找HGDIOBJ句柄引用的GDI对象类型,即它是钢笔,画笔,位图,字体还是区域?我找不到能胜任这项工作的WINAPI.当然,我总是可以采用棘手的方法来确定HGDIOBJ hTestedObj的类型:创建虚拟hDc,hPen,hBrush,hBitmap,hFont,hRegion;将这些虚拟对象选择为hDc,然后将SelectObject(hDc,hTestedObj)返回的句柄与hPen,hBrush等进行比较.以下代码说明了这一想法.
const CHAR * GdiType(HGDIOBJ hTestedObj){
HDC hDc = CreateCompatibleDC(GetDC(NULL));
assert(hDc!= NULL);
HGDIOBJ hPen = GetStockObject(DC_PEN);
HGDIOBJ hBrush = GetStockObject(DC_BRUSH);
HGDIOBJ hFont = GetStockObject(ANSI_FIXED_FONT);
HGDIOBJ hBitmap = CreateCompatibleBitmap(GetDC(NULL),1,1);
assert(hBitmap!= NULL);
HRGN hRegion = CreateRectRgn(0,0,1,1);
assert(hRegion);
HGDIOBJ hTemp = NULL;
hTemp = SelectObject(hDc,hPen); assert(hTemp!= NULL);
hTemp = SelectObject(hDc,hBrush); assert(hTemp!= NULL);
hTemp = SelectObject(hDc,hFont); assert(hTemp!= NULL);
hTemp = SelectObject(hDc,hBitmap); assert(hTemp!= NULL);
hTemp = SelectObject(hDc,hRegion);声明(hTemp!= HGDI_ERROR);
const CHAR * szRet =?";
hTemp = SelectObject(hDc,hTestedObj);
assert(hTemp!= NULL&&hTemp!= HGDI_ERROR);
if(hTemp == hPen)szRet ="PEN";
否则if(hTemp == hBrush)szRet ="BRUSH";
否则if(hTemp == hFont)szRet ="FONT";
否则if(hTemp == hBitmap)szRet ="BITMAP";
否则if(hTemp == hRegion || hTemp ==(HGDIOBJ)SIMPLEREGION ||
hTemp ==(HGDIOBJ)COMPLEXREGION ||
; hTemp ==(HGDIOBJ)NULLREGION)szRet ="REGION";
DeleteObject(hBitmap);
DeleteObject(hRegion);
DeleteDC(hDc);
return szRet;
}
但是此技术似乎有些尴尬(尽管它可以工作).
Is there an easy way to find out what type of GDI object is referenced by HGDIOBJ handle i.e. is it a pen, brush, bitmap, font or region? I can''t find WINAPI that does the job. Of course, I can always go the tricky way to determine the type of HGDIOBJ hTestedObj: create a dummy hDc, hPen, hBrush, hBitmap, hFont, hRegion; select these dummy objects into hDc, then compare the handle returned by SelectObject(hDc,hTestedObj) with hPen, hBrush, etc. The following code illustrates the idea.
const CHAR* GdiType(HGDIOBJ hTestedObj){
HDC hDc=CreateCompatibleDC(GetDC(NULL));
assert(hDc!=NULL);
HGDIOBJ hPen=GetStockObject(DC_PEN);
HGDIOBJ hBrush=GetStockObject(DC_BRUSH);
HGDIOBJ hFont=GetStockObject(ANSI_FIXED_FONT);
HGDIOBJ hBitmap=CreateCompatibleBitmap(GetDC(NULL),1,1);
assert(hBitmap!=NULL);
HRGN hRegion=CreateRectRgn(0,0,1,1);
assert(hRegion);
HGDIOBJ hTemp=NULL;
hTemp=SelectObject(hDc,hPen);assert(hTemp!=NULL);
hTemp=SelectObject(hDc,hBrush);assert(hTemp!=NULL);
hTemp=SelectObject(hDc,hFont);assert(hTemp!=NULL);
hTemp=SelectObject(hDc,hBitmap);assert(hTemp!=NULL);
hTemp=SelectObject(hDc,hRegion);assert(hTemp!=HGDI_ERROR);
const CHAR *szRet="?";
hTemp=SelectObject(hDc,hTestedObj);
assert(hTemp!=NULL && hTemp!=HGDI_ERROR);
if(hTemp==hPen)szRet="PEN";
else if(hTemp==hBrush)szRet="BRUSH";
else if(hTemp==hFont)szRet="FONT";
else if(hTemp==hBitmap)szRet="BITMAP";
else if(hTemp==hRegion || hTemp==(HGDIOBJ)SIMPLEREGION ||
hTemp==(HGDIOBJ)COMPLEXREGION ||
hTemp==(HGDIOBJ)NULLREGION)szRet="REGION";
DeleteObject(hBitmap);
DeleteObject(hRegion);
DeleteDC(hDc);
return szRet;
}
But this technique seems somewhat awkward (though it works). Perhaps, there is an elegant way to do the same thing?
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