一小部分是缺少在這裏,但不應該添加一個問題...
unit Unit3;
// 20121108 by Thomas Wassermann
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, jpeg;
type
TForm3 = class(TForm)
Image1: TImage;
PaintBox1: TPaintBox;
procedure FormCreate(Sender: TObject);
procedure PaintBox1Paint(Sender: TObject);
procedure PaintBox1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
procedure PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
private
{ Private-Deklarationen }
FDownPoint, FCurrentPoint: TPoint;
public
{ Public-Deklarationen }
end;
var
Form3: TForm3;
implementation
uses Math;
{$R *.dfm}
procedure TForm3.FormCreate(Sender: TObject);
begin
PaintBox1.BringToFront;
end;
type
pRGBQuadArray = ^TRGBQuadArray;
TRGBQuadArray = ARRAY [0 .. $EFFFFFF] OF TRGBQuad;
Procedure SetAlpha(bmp: TBitMap; Alpha: Byte; R: TRect);
var
pscanLine32: pRGBQuadArray;
i, j: Integer;
begin
bmp.PixelFormat := pf32Bit;
bmp.HandleType := bmDIB;
bmp.ignorepalette := true;
bmp.alphaformat := afDefined;
for i := 0 to bmp.Height - 1 do
begin
pscanLine32 := bmp.Scanline[i];
for j := 0 to bmp.Width - 1 do
begin
if (j >= R.Left) and (j <= R.Right) and (i >= R.Top) and (i <= R.Bottom) then
begin
pscanLine32[j].rgbReserved := 0;
pscanLine32[j].rgbBlue := 0;
pscanLine32[j].rgbRed := 0;
pscanLine32[j].rgbGreen := 0;
end
else
begin
pscanLine32[j].rgbReserved := Alpha;
pscanLine32[j].rgbBlue := Alpha;
pscanLine32[j].rgbRed := Alpha;
pscanLine32[j].rgbGreen := Alpha;
end;
end;
end;
end;
procedure TForm3.PaintBox1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
FDownPoint.X := X;
FDownPoint.Y := Y;
FCurrentPoint := FDownPoint;
PaintBox1.Invalidate;
end;
procedure TForm3.PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
begin
if ssLeft in Shift then
begin
FCurrentPoint.X := X;
FCurrentPoint.Y := Y;
PaintBox1.Invalidate;
end;
end;
procedure TForm3.PaintBox1Paint(Sender: TObject);
var
bmp: TBitMap;
SelRect: TRect;
begin
bmp := TBitMap.Create;
try
bmp.Width := PaintBox1.Width;
bmp.Height := PaintBox1.Height;
if (FCurrentPoint.X = FDownPoint.X) and (FCurrentPoint.Y = FDownPoint.Y) then
SelRect := PaintBox1.BoundsRect
else
begin
SelRect.Left := Min(FCurrentPoint.X, FDownPoint.X);
SelRect.Top := Min(FCurrentPoint.Y, FDownPoint.Y);
SelRect.Right := Max(FCurrentPoint.X, FDownPoint.X);
SelRect.Bottom := Max(FCurrentPoint.Y, FDownPoint.Y);
end;
SetAlpha(bmp, 140, SelRect);
PaintBox1.Canvas.Draw(0, 0, bmp);
finally
bmp.Free;
end;
end;
end.
這個解決方案的嘗試使用覆顏料盒,同樣clientrect的圖像,對於所有的繪圖和選擇。通過使用mouse/down/move生成的座標,創建一個半透明的位圖,它在選定的矩形中是完全透明的。生成後,它被塗在油漆盒上。進一步的繪畫可以在那裏完成。框架,錨,十字準線。任何用戶操作都必須以mousedown捕捉,具體取決於所選部分,例如。一個錨的大小可以完成。 通常我更喜歡GDI +這樣的請求,但如圖所示,不需要額外的單位。來源:http://www.bummisoft.de/download/transparenteauswahl.zip
如果你添加了一些文本來解釋爲什麼你的代碼正在做它做什麼以及如何實現OP的目標,你的答案會好得多。它使得它更容易遵循... –
我完全同意Marjan。只有代碼的答案可能會有所幫助,但通過一些說明和解釋可以大大提高答案。這是一個複雜的主題,值得散文。 –
我同意,由於窗戶是重新啓動的意見(他是死的吉姆(谷歌)),所以輸入了更長的信息。我會再做一次。 – bummi