在开发“518抽奖软件”的时候,需要用到GDI+的写文字功能。 GDI+在对齐方面比原来的GDI复杂些,主要是 StringFormat 的参数设置和行高的测定问题,详情参考下面的源码。
GDIPLUS(gdi+)对齐处理的函数源码
//单行文本,rc内对齐,align是水平对齐,valign是垂直对齐
//
void Tapp::paint_str(HDC hDc, const WCHAR* str, LOGFONT& lf, COLORREF color, RECT& rc, WORD align, WORD valign)
{
if (!str) return;
if (rc.right - rc.left <= 1 || rc.bottom - rc.top <= 1) return;
StringFormat fmt;
fmt.SetFormatFlags(StringFormatFlagsNoWrap | StringFormatFlagsNoClip | StringFormatFlagsMeasureTrailingSpaces);
if (align == ALIGN_NEAR) fmt.SetAlignment(StringAlignmentNear);
else if (align == ALIGN_CENTER) fmt.SetAlignment(StringAlignmentCenter);
else fmt.SetAlignment(StringAlignmentFar);
fmt.SetLineAlignment(StringAlignmentNear);
RectF rcF;
rcF.X = rc.left;
rcF.Y = rc.top;
rcF.Width = rc.right - rc.left;
rcF.Height = rc.bottom - rc.top;
FontFamily ff(lf.lfFaceName);
Font gfont(hDc, &lf);
SolidBrush bru(Color(GetRValue(color), GetGValue(color), GetBValue(color)));
Graphics g(hDc);
int style = FontStyleRegular;
if (lf.lfItalic) style = FontStyleItalic;
if (lf.lfWeight == FW_BOLD) style = FontStyleBold;
if (lf.lfItalic && lf.lfWeight == FW_BOLD) style = FontStyleBoldItalic;
double r = (double)(ff.GetCellAscent(style) + ff.GetCellDescent(style)) / (double)ff.GetLineSpacing(style);
if (align == ALIGN_NEAR) rcF.Width += 500.0;
else if (align == ALIGN_FAR) { rcF.X -= 500.0; rcF.Width += 500.0; }
else { rcF.X -= 500.0; rcF.Width += 1000.0; }
if (valign == ALIGN_NEAR) rcF.Height += 500.0;
else if (valign == ALIGN_CENTER) {
rcF.Y -= 500.0;
rcF.Height += 1000.0;
rcF.Y += ((rcF.Height - gfont.GetHeight(&g)*r) / 2.0);
}
else {
rcF.Y -= 500.0;
rcF.Height += 500.0;
rcF.Y += (rcF.Height - gfont.GetHeight(&g)*r);
}
SetTextRenderingHint(TextRenderingHintAntiAlias);
g.DrawString(str, -1, &gfont, rcF, &fmt, &bru);
}