摘要：
程序比较GDI和GDI+绘图。经过比较，GDI比GDI+具有一些性能优势。同时，我们比较了TGPGraphics对象的创建和每次绘制时共享一个TGPGrapgraphics对象的情况。这两个对象的性能几乎相同，可以忽略不计。
编写程序对GDI和GDI+绘制进行了比较，经过比较，GDI相对GDI+还是有一些性能优势的。
同时比较了每次绘制创建TGPGraphics对象和共用一个TGPGraphics对象的情况，两者性能相差不大，几可忽略。
1.用GDI绘制5K次----耗时约为19s200ms
procedure TForm8.WMPaint(var Message: TWMPaint);
var
ps: PAINTSTRUCT;
LClientRect: TGPRect;
LGraph: TGPGraphics;
LBrush: TGPBrush;
LBr: HGDIOBJ;
begin
if m_nCount < 5000 then
begin
//创建缓存
BeginPaint(Handle, ps);
if not Assigned(m_memDC) then
m_memDC := TMemoryDC.Create(ps.hdc);
m_memDC.SetBounds(ps.hdc, Self.ClientRect);
//用GDI+绘制
// LBrush := TGPSolidBrush.Create(aclRed);
// LClientRect := MakeRect(Self.ClientRect);
// m_memDC.Graph.FillRectangle(LBrush, LClientRect);
// LBrush.Free;
//用GDI绘制
LBr := CreateSolidBrush(clRed);
FillRect(m_memDC.DC, Self.ClientRect, LBr);
DeleteObject(LBr);
//缓冲去拷贝
m_memDC.Blt(ps.hdc);
EndPaint(Handle, ps);
Message.Result := 0;
Inc(m_nCount);
end
else
begin
BeginPaint(Handle, ps);
EndPaint(Handle, ps);
Message.Result := 0;
end;
end;
2.用GDI+绘制5K次----耗时约为19s600ms
procedure TForm8.WMPaint(var Message: TWMPaint);
var
ps: PAINTSTRUCT;
LClientRect: TGPRect;
LGraph: TGPGraphics;
LBrush: TGPBrush;
LBr: HGDIOBJ;
begin
if m_nCount < 5000 then
begin
//创建缓存
BeginPaint(Handle, ps);
if not Assigned(m_memDC) then
m_memDC := TMemoryDC.Create(ps.hdc);
m_memDC.SetBounds(ps.hdc, Self.ClientRect);
//用GDI+绘制
LGraph := TGPGraphics.Create(m_memDC.DC);
LBrush := TGPSolidBrush.Create(aclRed);
LClientRect := MakeRect(Self.ClientRect);
LGraph.FillRectangle(LBrush, LClientRect);
LGraph.Free;
LBrush.Free;
//用GDI绘制
// LBr := CreateSolidBrush(clRed);
// FillRect(m_memDC.DC, Self.ClientRect, LBr);
// DeleteObject(LBr);
//缓冲去拷贝
m_memDC.Blt(ps.hdc);
EndPaint(Handle, ps);
Message.Result := 0;
Inc(m_nCount);
end
else
begin
BeginPaint(Handle, ps);
EndPaint(Handle, ps);
Message.Result := 0;
end;
end;
3.用GDI+绘制5K次(不重复创建TGPGraphics)----耗时约为19s500ms
procedure TForm8.WMPaint(var Message: TWMPaint);
var
ps: PAINTSTRUCT;
LClientRect: TGPRect;
LGraph: TGPGraphics;
LBrush: TGPBrush;
LBr: HGDIOBJ;
begin
if m_nCount < 5000 then
begin
//创建缓存
BeginPaint(Handle, ps);
if not Assigned(m_memDC) then
m_memDC := TMemoryDC.Create(ps.hdc);
m_memDC.SetBounds(ps.hdc, Self.ClientRect);
//用GDI+绘制
LBrush := TGPSolidBrush.Create(aclRed);
LClientRect := MakeRect(Self.ClientRect);
m_memDC.Graph.FillRectangle(LBrush, LClientRect);
LBrush.Free;
//用GDI绘制
// LBr := CreateSolidBrush(clRed);
// FillRect(m_memDC.DC, Self.ClientRect, LBr);
// DeleteObject(LBr);
//缓冲去拷贝
m_memDC.Blt(ps.hdc);
EndPaint(Handle, ps);
Message.Result := 0;
Inc(m_nCount);
end
else
begin
BeginPaint(Handle, ps);
EndPaint(Handle, ps);
Message.Result := 0;
end;
end;