mainform.cpp

C++Builder程序员编程手记《配书光盘》

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "MainForm.h"
#include "math.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
  : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
	RotatePoints();
  if(TextZoom)
  {
    if(TextSize<=50)
    {
      ShowText(TextPosition.x,TextPosition.y,TextSize);
      TextSize+=3;
    }
    else
      TextZoom=false;
  }
  else
  {
    if(TextSize>0)
    {
      ShowText(TextPosition.x,TextPosition.y,TextSize);
      TextSize-=3;
    }
    else
      TextZoom=true;
  }
	Invalidate();
}
//---------------------------------------------------------------------
void __fastcall TForm1::RotatePoints()
{
	const float M_2PI = 2 * M_PI;           // 2 pi radians in a circle
	float StepAngle = M_2PI / PointCount;   // 相邻节点间的夹角弧度

	Rotation += M_PI / 32;                  // 起始旋转角度
	if (Rotation > StepAngle)               // 如果起始旋转角度大于两点的夹角
		Rotation -= StepAngle;                // 那么保持起始旋转角度不超过两点的夹角

	// 下面的循环中，循环变量i用来遍历节点数组中所有节点，循环变量j用来增加每一个
	// 节点的旋转角度，将其起始旋转角度设置为Rotation，可以保持图形的顺时针旋转，
	// 旋转的增量为两点间的夹角
	int i;
	float j;
	for (i = 0, j = Rotation; i < PointCount; i++, j += StepAngle) {
		Points[i].X = cos(j);
		Points[i].Y = sin(j);
  //上述坐标将用来和当前的半径相乘
	}
}
//---------------------------------------------------------------------

void __fastcall TForm1::FormCreate(TObject *Sender)
{
	Canvas->Pen->Color = clTeal;
	Rotation = 0;
	PointCount = MaxPoints;
  TextSize=0;
  TextZoom=true;
  TextPosition.x=ClientWidth*3/4;
  TextPosition.y=ClientHeight/2;
  Label1->Caption=Edit2->Text;
  CheckBox1->Checked=true;
  RotatePoints();
}
//---------------------------------------------------------------------------

void __fastcall TForm1::FormPaint(TObject *Sender)
{
	int centerX = ClientWidth / 2;
	int centerY = ClientHeight / 2;
	int radius = min(centerY, centerX);

	int i,j;
	for (i = 0; i < PointCount; i++) {
		for (j = i + 1; j < PointCount; j++) {
			Canvas->MoveTo(radius + floor(Points[i].X * radius),
				radius + floor(Points[i].Y * radius));
			Canvas->LineTo(radius + floor(Points[j].X * radius),
				radius + floor(Points[j].Y * radius));
		}
	}
}
//---------------------------------------------------------------------------

void __fastcall TForm1::FormResize(TObject *Sender)
{
  TextPosition.x=ClientWidth*3/4;
  TextPosition.y=ClientHeight/2;
	Invalidate();
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Edit1Change(TObject *Sender)
{
  Timer1->Interval=StrToInt(Edit1->Text);
}
//---------------------------------------------------------------------------
void TForm1::ShowText(int X, int Y, int Size)
{
  Label1->Left=X;
  Label1->Top=Y;
  Label1->Font->Size=Size;
}
void __fastcall TForm1::Edit2Change(TObject *Sender)
{
  Label1->Caption=Edit2->Text;  
}
//---------------------------------------------------------------------------

void __fastcall TForm1::FormMouseUp(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
  TextPosition.x=X;
  TextPosition.y=Y;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::CheckBox1Click(TObject *Sender)
{
  Timer1->Enabled=CheckBox1->Checked;
}
//---------------------------------------------------------------------------