Rendre transparente une Form a partir d'un cercle central
Un bout de code qui rend une Form transparante du centre vers les bords a partir d'un cercle qui grandit
le .cpp
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//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
#include <math.hpp>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
// on retire les bordures
Form1->BorderStyle = bsNone;
// on parametre la Form pour le mode transparent
Form1->TransparentColor = true;
Form1->TransparentColorValue = clWhite;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
int cmpt = 0;
int a;
int b;
// on dimensionne la Form en plein ecran
Form1->Top = 0;
Form1->Left = 0;
Form1->Width = Screen->Width;
Form1->Height = Screen->Height;
// on calcule la diagonale ecran qui part du centre vers un coin ecran
a = Form1->Height;
b = Form1->Width;
cmpt = (Hypot(a, b) + 1) / 2;
// on trace un cercle avec la couleur transparente (blanc)
for(int i =0; i <= cmpt; i++)
{
Sleep(20); // temporisation
Form1->Canvas->Pen->Color = clBtnFace; // pas de trait sur la circonferance
Form1->Canvas->Brush->Color = clWhite; // couleur du fond
Form1->Canvas->Ellipse((Form1->Width / 2) - i, (Form1->Height / 2) + i, (Form1->Width / 2) + i, (Form1->Height / 2) - i);
}
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
Form1->Close();
}
//--------------------------------------------------------------------------- |
le .h
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//---------------------------------------------------------------------------
#ifndef Unit1H
#define Unit1H
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published: // IDE-managed Components
TButton *Button1;
TButton *Button2;
void __fastcall Button1Click(TObject *Sender);
void __fastcall Button2Click(TObject *Sender);
private: // User declarations
public: // User declarations
__fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif |
