如何解决使用wingdi函数一起缩放和旋转SetWorldTransform
我正在使用ExtTextOut wingdi函数绘制文本。另外,我正在使用SetWorldTransform缩放文本,但是现在我也想旋转文本(所有角度)。如何更改/传递参数,使其也能缩放和旋转?
下面是示例代码块,此代码可以完美运行,但现在我也想介绍旋转文本,而不会影响缩放比例。
var inputString = "Sample text";
var fontSize = 31f;
var font = new Font("Avenir Black",fontSize,new FontStyle());
var startX1 = 50;
var startY1 = 50;
LOGFONT lf = new LOGFONT();
font.ToLogFont(lf,e.Graphics);
IntPtr hPrinterDC = e.Graphics.GetHdc();
StringBuilder sbText = new StringBuilder(inputString);
if (hPrinterDC != IntPtr.Zero)
{
int nPrintHorzRes = GetDeviceCaps(hPrinterDC,HORZRES);
int nPrintVertRes = GetDeviceCaps(hPrinterDC,VERTRES);
int nPhysWidth = GetDeviceCaps(hPrinterDC,PHYSICALWIDTH);
int nPhysHeight = GetDeviceCaps(hPrinterDC,PHYSICALHEIGHT);
int nPhysOffsetX = GetDeviceCaps(hPrinterDC,PHYSICALOFFSETX);
int nPhysOffsetY = GetDeviceCaps(hPrinterDC,PHYSICALOFFSETY);
IntPtr hDCScreen = GetDC(IntPtr.Zero);
float nLogPixelsXScreen = GetDeviceCaps(hDCScreen,LOGPIXELSX);
float nLogPixelsYScreen = GetDeviceCaps(hDCScreen,LOGPIXELSY);
ReleaseDC(hDCScreen,IntPtr.Zero);
float nLogPixelsXPrinter = GetDeviceCaps(hPrinterDC,LOGPIXELSX);
float nLogPixelsYPrinter = GetDeviceCaps(hPrinterDC,LOGPIXELSY);
float nScaleX = Math.Max(nLogPixelsXScreen,nLogPixelsXPrinter) / Math.Min(nLogPixelsXScreen,nLogPixelsXPrinter);
float nScaleY = Math.Max(nLogPixelsYScreen,nLogPixelsYPrinter) / Math.Min(nLogPixelsYScreen,nLogPixelsYPrinter);
System.Drawing.Drawing2D.Matrix transform = new System.Drawing.Drawing2D.Matrix();
transform.Scale(nScaleX,nScaleY);
XFORM renderTransform = new XFORM();
var elements = transform.Elements;
var m11 = elements[0];
var m12 = elements[1];
var m21 = elements[2];
var m22 = elements[3];
var dx = elements[4];
var dy = elements[5];
renderTransform.eM11 = (float)m11;
renderTransform.eM12 = (float)m12;
renderTransform.eM21 = (float)m21;
renderTransform.eM22 = (float)m22;
int nOffsetX = 0;
int nOffsetY = 0;
renderTransform.eDx = (float)transform.OffsetX + nOffsetX;
renderTransform.eDy = (float)transform.OffsetY + nOffsetY;
SetGraphicsMode(hPrinterDC,GM_ADVANCED);
SetMapMode(hPrinterDC,MM_TEXT);
bool bRet = SetWorldTransform(hPrinterDC,ref renderTransform);
var startX2 = startX1;
var startY2 = startY1;
RECT rc = new RECT(startX2,startY2,nPhysWidth,nPhysHeight);
SetViewportOrgEx(hPrinterDC,-nPhysOffsetX,-nPhysOffsetY,IntPtr.Zero);
lf.lfHeight = (int)(lf.lfHeight / nScaleY);
IntPtr hFontNew = CreateFontIndirect(lf);
IntPtr hFontOld = SelectObject(hPrinterDC,hFontNew);
SetBkMode(hPrinterDC,TRANSPARENT);
SetTextColor(hPrinterDC,ColorTranslator.ToWin32(Color.Blue));
ExtTextOut(hPrinterDC,rc.left,rc.top,ETO_OPAQUE,IntPtr.Zero,sbText,(uint)sbText.Length,IntPtr.Zero);
rc.top += -lf.lfHeight;
SetTextColor(hPrinterDC,ColorTranslator.ToWin32(Color.Green));
ExtTextOut(hPrinterDC,IntPtr.Zero);
var nExtra = -10.0f / nScaleX;
SetTextCharacterExtra(hPrinterDC,(int)nExtra);
rc.top += -lf.lfHeight;
SetTextColor(hPrinterDC,ColorTranslator.ToWin32(Color.Red));
ExtTextOut(hPrinterDC,IntPtr.Zero);
SelectObject(hPrinterDC,hFontOld);
DeleteObject(hFontNew);
}
这是pinvokes:
[DllImport("Gdi32.dll",SetLastError = true,CharSet = CharSet.Unicode)]
public static extern bool SetWorldTransform(IntPtr hdc,ref XFORM lpxf);
[StructLayout(LayoutKind.Sequential)]
public struct XFORM
{
public float eM11;
public float eM12;
public float eM21;
public float eM22;
public float eDx;
public float eDy;
}
[DllImport("Gdi32.dll",CharSet = CharSet.Unicode)]
public static extern int SetGraphicsMode(IntPtr hdc,int iMode);
public const int GM_COMPATIBLE = 1;
public const int GM_ADVANCED = 2;
public const int GM_LAST = 2;
[DllImport("User32.dll",CharSet = CharSet.Auto)]
public static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("User32.dll",CharSet = CharSet.Auto)]
public static extern int ReleaseDC(IntPtr hWnd,IntPtr hDC);
public const int TRANSPARENT = 1;
public const int OPAQUE = 2;
public const int BKMODE_LAST = 2;
[DllImport("Gdi32.dll",CharSet = CharSet.Unicode)]
public static extern int SetBkMode(IntPtr hdc,int mode);
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