unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComCtrls, ExtCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
TrackBar1: TTrackBar;
LabeledEdit1: TLabeledEdit;
LabeledEdit2: TLabeledEdit;
procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure FormPaint(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure TrackBar1Change(Sender: TObject);
procedure LabeledEdit1Change(Sender: TObject);
procedure LabeledEdit2Change(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
PtArr: array of TGPPoint;
i: Integer = 0;
tension: Single; //因为我们要用到的曲度值要精确到小数,所以此变量为single类型
procedure TForm1.FormCreate(Sender: TObject);
begin
Button1.Caption := '擦除';
LabeledEdit1.EditLabel.Caption := '第几点开始';
LabeledEdit2.EditLabel.Caption := '画几段';
LabeledEdit1.Text := '0';
LabeledEdit2.Text := '0';
TrackBar1.ShowSelRange := False; //这段代码可有可无,但加上这个我觉得跟踪条会更好看些
TrackBar1.Min := -25;
TrackBar1.Max := 35;
TrackBar1.Position := 5;
end;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Inc(i);
SetLength(PtArr, i);
PtArr[i-1].X := X;
PtArr[i-1].Y := Y;
LabeledEdit2.Text := IntToStr(i-1);
Text := IntToStr(i);
Repaint;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
p: TGPPen;
i,n1,n2: Integer;
begin
Form1.DoubleBuffered:=True; //双缓冲
g := TGPGraphics.Create(Canvas.Handle);
p := TGPPen.Create(aclRed, 2);
g.Clear(aclWhite);
n1 := StrToIntDef(LabeledEdit1.Text, 0);
n2 := StrToIntDef(LabeledEdit2.Text, Length(PtArr)-1);
g.SetSmoothingMode(SmoothingModeHighQuality); //设置高质量抗锯齿
{第4,5,6参数为可选,第4参数是从第几点开始画,第5参数是画几段,
第6参数为曲度值,这里是 0.5, 如果为 0 时曲线会转为直线段}
g.DrawCurve(p, PGPPoint(PtArr), Length(PtArr), n1, n2, tension); //画曲线
p.SetWidth(1);
p.SetColor(aclBlack);
for i := 0 to Length(PtArr) - 1 do
g.DrawEllipse(p, PtArr[i].X-2, PtArr[i].Y-2, 4, 4);
g.Free;
p.Free;
end;
procedure TForm1.LabeledEdit1Change(Sender: TObject);
var
a,b: Integer;
begin {看画曲线的第4,第5参数,也就是n1,n2,下面代码就是控制n1不能小0,
因为不能从负数点开始画起,也不能大于(所画的点数-2),因为我们最起码要它画一段}
a := StrToIntDef(LabeledEdit1.Text, 0);
if (a < 0) or (a > Length(PtArr) - 2) then
LabeledEdit1.Text := IntToStr(0);
a := StrToIntDef(LabeledEdit1.Text, 0);
b := StrToIntDef(LabeledEdit2.Text, 0);
if a+b > Length(PtArr)-1 then //如果n1,n2的和大于最后那一点的数值,那么就超出范围了
LabeledEdit2.Text := IntToStr(Length(PtArr)-1-a);
Repaint;
end;
procedure TForm1.LabeledEdit2Change(Sender: TObject);
var
a,b: Integer;
begin
a := StrToIntDef(LabeledEdit1.Text, 0);
b := StrToIntDef(LabeledEdit2.Text, 0);
if (b < 0) or (b >= Length(PtArr) - a) then //画负数段和画超出范围的段数都不行的
LabeledEdit2.Text := IntToStr(Length(PtArr)-1-a);
Repaint;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
tension := TrackBar1.Position / 10;
Repaint;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
i := 0;
SetLength(PtArr, i);
LabeledEdit1.Text:=IntToStr(i); //既然所画的点被擦除了,那么这两个标签编辑框也应该清0了。
LabeledEdit2.Text:=IntToStr(i);
Repaint;
Text := IntToStr(i);
end;
end.