Description

This example shows how to use the TCanvas fill functions and their results.

The TCanvas fill functions are: Fill, FillArc, FillEllipse, FillPath, FillPolygon, FillRect, FillText.

To build and test this example, create a FireMonkey HD Application - C++ and add the following controls on the form:

A TImage
A TGroupBox with six TRadioButton objects (a radio button for each function, except for Fill). Change the TRadioButton.Text property for each radio button with the name of a function.
A TButton
A TColorComboBox

The example draws on the canvas of the bitmap. The bitmap is displayed on the TImage.

Code

Add the following code to the OnCreate event handler of the form.

void __fastcall TForm2::FormCreate(TObject *Sender) {
        // initializes the image bitmap canvas 
        Image1->Bitmap = new TBitmap(400, 400);
        Image1->Bitmap->Clear(claWhite);
}

Add the following code, which makes the drawing area white, to the OnClick event handler of the button.

void __fastcall TForm2::Button1Click(TObject *Sender) {
        // clears the canvas
        Image1->Bitmap->Canvas->Clear(claWhite);
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}

Add the following code, which changes the fill color of the canvas, to the OnExit event handler of the ColorComboBox.

void __fastcall TForm2::ColorComboBox1Exit(TObject *Sender) {
        // sets the fill color of the canvas to the value from the ColorComboBox 
        Image1->Bitmap->Canvas->Fill->Color = ColorComboBox1->Color;
}

Add the following codes to the OnClick event handlers of each radio button.

Code

void __fastcall TForm2::RadioButton11Click(TObject *Sender) {
        // sets the center and the radius of the arc
        TPointF p1(200, 200), p2(150, 150);
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the arc on the canvas
        Image1->Bitmap->Canvas->FillArc(p1, p2, 90, 230, 20);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
 
}
// ---------------------------------------------------------------------------
 
void __fastcall TForm2::RadioButton12Click(TObject *Sender) {
        // sets the circumscribed rectangle of the ellipse
        TRectF MyRect(50, 40, 200, 270);
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the ellipse on the canvas
        Image1->Bitmap->Canvas->FillEllipse(MyRect, 40);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}
// ---------------------------------------------------------------------------
 
void __fastcall TForm2::RadioButton13Click(TObject *Sender) {
        TPathData* path;
        // sets the circumscribed rectangle of the ellipse to be added to the path
        TRectF MyRect1(90, 100, 230, 300), MyRect2(70, 90, 220, 290);
        // initializes and creates the path to be drawn
        path = new TPathData;
        path->AddEllipse(MyRect1);
        path->AddRectangle(MyRect2, 0, 0, AllCorners);
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the path on the canvas
        Image1->Bitmap->Canvas->FillPath(path, 200);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}
// ---------------------------------------------------------------------------
 
void __fastcall TForm2::RadioButton14Click(TObject *Sender) {
        // sets the rectangle to be drawn
        TRectF MyRect(50, 40, 200, 270);
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the rectangle on the canvas
        Image1->Bitmap->Canvas->FillRect(MyRect, 30, 60, AllCorners, 100);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}
// ---------------------------------------------------------------------------
 
void __fastcall TForm2::RadioButton15Click(TObject *Sender) {
        // sets the points that define the polygon
        TPointF p1(210, 220), p2(330, 360), p3(380, 260), p4(200, 180),
                p5(140, 160);
        TPolygon MyPolygon;
        // creates the polygon
        MyPolygon.set_length(5);
        MyPolygon[0] = p1;
        MyPolygon[1] = p2;
        MyPolygon[2] = p3;
        MyPolygon[3] = p4;
        MyPolygon[4] = p5;
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the polygon on the canvas
        Image1->Bitmap->Canvas->FillPolygon(MyPolygon, 50);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}
// ---------------------------------------------------------------------------
 
void __fastcall TForm2::RadioButton16Click(TObject *Sender) {
        // sets the rectangle where the text will be displayed
        TRectF MyRect(50, 40, 200, 270);
        Image1->Bitmap->Canvas->BeginScene();
        // fills and draws the text in the specified rectangle area of the canvas
        Image1->Bitmap->Canvas->FillText(MyRect, "FillText", false, 100,
                TFillTextFlags(TFillTextFlag::ftRightToLeft), taCenter, taCenter);
        Image1->Bitmap->Canvas->EndScene();
        // updates the bitmap
        Image1->Bitmap->BitmapChanged();
}
// ---------------------------------------------------------------------------