我期待在CodeGear Delphi 2010中绘制一个不透明椭圆.
我试图绘制另一个位图,
我设置了位图透明色(用于背景)
调用椭圆方法.
在我的图像中,我使用不透明度参数(来自重载)绘制位图.但它不起作用.
我想要这样的东西http://www.java2s.com/Tutorial/VBImages/WPF-UseOpacityMaskAndRadialGradientBrush.PNG
有人知道一种工作方法吗？
解决方法
这个对我有用：
procedure TForm1.Button1Click(Sender: TObject);
var
bm1,bm2: TBitmap;
begin
bm1 := TBitmap.Create;
bm1.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\portrait.bmp');
bm2 := TBitmap.Create;
bm2.SetSize(bm1.Width,bm1.Height);
bm2.Canvas.Brush.Color := clRed;
bm2.Canvas.Pen.Style := psClear;
bm2.Canvas.Ellipse(0,bm2.Width,bm2.Height);
Canvas.Draw(100,100,bm1);
Canvas.Draw(100,bm2,127);
end;
Sample 1 http://privat.rejbrand.se/blendimg1.png
如果您想要更多控制,您可以随时手动进行处理：
procedure TForm1.Button1Click(Sender: TObject);
type
TRGB32Array = packed array[0..MaxInt div SizeOf(TRGBQuad)-1] of TRGBQuad;
PRGB32Array = ^TRGB32Array;
TScanline = TRGB32Array;
PScanline = ^TScanline;
var
bm1,bm3: TBitmap;
sc1,sc2,sc3: PScanline;
i: Integer;
j: Integer;
var
transp: real;
const
opacity = 0.29;
begin
transp := 1 - opacity;
bm1 := TBitmap.Create;
bm1.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\portrait.bmp');
bm2 := TBitmap.Create;
bm2.SetSize(bm1.Width,bm2.Height);
bm3 := TBitmap.Create;
bm3.SetSize(bm1.Width,bm1.Height);
bm1.PixelFormat := pf32bit;
bm2.PixelFormat := pf32bit;
bm3.PixelFormat := pf32bit;
for i := 0 to bm1.Height - 1 do
begin
sc1 := bm1.ScanLine[i];
sc2 := bm2.ScanLine[i];
sc3 := bm3.ScanLine[i];
for j := 0 to bm1.Width - 1 do
with sc3^[j] do
begin
rgbBlue := round(transp*sc1^[j].rgbBlue + opacity*sc2^[j].rgbBlue);
rgbGreen := round(transp*sc1^[j].rgbGreen + opacity*sc2^[j].rgbGreen);
rgbRed := round(transp*sc1^[j].rgbRed + opacity*sc2^[j].rgbRed);
end;
end;
Canvas.Draw(100,bm3);
end;
Sample 2 http://privat.rejbrand.se/blendimg2.png
例如,您可以让背景图像在椭圆外的100％不透明度：
...
for i := 0 to bm1.Height - 1 do
begin
sc1 := bm1.ScanLine[i];
sc2 := bm2.ScanLine[i];
sc3 := bm3.ScanLine[i];
for j := 0 to bm1.Width - 1 do
if sc2^[j].rgbBlue + sc2^[j].rgbGreen + sc2^[j].rgbRed = 3*255 then
sc3^[j] := sc1^[j]
else
with sc3^[j] do
begin
rgbBlue := round(transp*sc1^[j].rgbBlue + opacity*sc2^[j].rgbBlue);
rgbGreen := round(transp*sc1^[j].rgbGreen + opacity*sc2^[j].rgbGreen);
rgbRed := round(transp*sc1^[j].rgbRed + opacity*sc2^[j].rgbRed);
end;
end;
...
Sample 3 http://privat.rejbrand.se/blendimg3.png
更不用说all other cool stuff you can do with pixmap manipulation：
...
for i := 0 to bm1.Height - 1 do
begin
sc1 := bm1.ScanLine[i];
sc2 := bm2.ScanLine[i];
sc3 := bm3.ScanLine[i];
for j := 0 to bm1.Width - 1 do
if sc2^[j].rgbBlue + sc2^[j].rgbGreen + sc2^[j].rgbRed = 3*255 then
sc3^[j] := sc1^[j]
else
with sc3^[j] do
begin
rgbBlue := round(sin(transp*sc1^[j].rgbBlue + opacity*sc2^[j].rgbBlue));
rgbGreen := round(transp*sc1^[j].rgbGreen + opacity*sc2^[j].rgbGreen);
rgbRed := round(transp*sc1^[j].rgbRed + opacity*sc2^[j].rgbRed);
end;
end;
...
Sample 4 http://privat.rejbrand.se/blendimg4.png
如果你真的不想手动操作,我只是想通了,你可以在第一个位图的副本上绘制椭圆,然后混合这两个位图：
procedure TForm1.Button1Click(Sender: TObject);
var
bm1,bm2: TBitmap;
begin
bm1 := TBitmap.Create;
bm1.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\portrait.bmp');
bm2 := TBitmap.Create;
bm2.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\portrait.bmp');
bm2.Canvas.Brush.Color := clRed;
bm2.Canvas.Pen.Style := psClear;
bm2.Canvas.Ellipse(0,127);
end;