Računarska grafika

1. Računarska grafika GDI+ (Graphics Device Interface Plus)

2. Introduction • Windows GDI+ is the portion of the Windows XP operating system or Windows Server 2003 operating system that provides two-dimensional vector graphics, imaging, and typography. GDI+ improves on Windows Graphics Device Interface (GDI) (the graphics device interface included with earlier versions of Windows) by adding new features and by optimizing existing features.

3. The namespaces in GDI+ • System.Drawing • This is the core GDI+ namespace. It defines objects for basic rendering (fonts, pens, basic brushes, etc.) and the most important object: Graphics. • System.Drawing.Drawing2D • This gives you objects for more advanced two-dimensional vector graphics. Some of them are gradient brushes, pen caps, and geometric transforms.

4. The namespaces in GDI+ • System.Drawing.Imaging • If you want to change graphical images - that is, change the palette, extract image metadata, manipulate metafiles, and so forth - this is the one you need. • System.Drawing.Printing • To render images to the printed page, interact with the printer itself, and format the overall appearance of a print job, use the objects here.

5. The namespaces in GDI+ • System.Drawing.Text • You can use collections of fonts with this namespace.

6. Graphics object • The place to start with GDI+ is the Graphics object. Although the things you draw show up on your monitor or a printer, the Graphics object is the "canvas" that you draw on. • Graphics object is always associated with a particular device context.

7. How do I get a Graphics object? • You can get Graphics object from other objects. (e.g.evente parameter that is passed to the OnPaint event) • You can use the CreateGraphicsmethod for a device context to create a Graphics object.

8. Example private void Form1_Paint(object sender, PaintEventArgs e) { Graphics g = e.Graphics; g.DrawLine(new Pen(Color.Red), 0, 0, 250, 250); } -or- protected override void OnPaint(PaintEventArgs e) { base.OnPaint(e); Graphics g = e.Graphics; g.DrawLine(new Pen(Color.Red), 0, 0, 250, 250); } -or- private void button1_Click(object sender, EventArgs e) { Graphics g = this.CreateGraphics(); g.DrawLine(new Pen(Color.Red), 0, 0, 250, 250); }

10. Vector Graphics versus Bitmaps • "vector"isanother word for a line, this way of using GDI+ is often called vector graphics. • The other major type of graphics is create graphics using individual points of color like your TV or computer monitor does it. This is calledbitmap graphics and will be covered in a later segment.

12. Coordinate spaces There are three distinct coordinate spaces in GDI+. These are: • World coordinate space. This is where you put the coordinates that define lines, shapes and points in the 2 dimensional space of the graphics system. World coordinates are abstract values expressed as floating point numbers. Essentially, whenever you draw something it goes into this coordinate space. • Page Coordinate Space. The Page space is where the world coordinates are transformed into some real-world value. You can make the Page Space represent pixels, inches millimeters and so-on. This is what makes GDI+ a resolution independent system. You control how the page space interprets the world space by telling the Graphics object what PageUnit is being used and adjusting the PageScale. • Device Coordinate Space. This space is controlled by the system and enables the real-world values in the Page Space to be translated to your screen or printer. Device space ensures that a 1 inch long line looks an inch long on the screen and on the printer even though the two devices may have very different pixel resolutions. You have no direct control over this space.

13. Defining coordinate begining & orentations Graphics g = e.Graphics; GraphicsStateStanjePre = g.Save(); g.PageUnit = GraphicsUnit.Pixel; MatrixmatricaTransformacija = new Matrix(1, 0, 0, -1, 0, 0); matricaTransformacija.Translate(this.ClientRectangle.Width / 2, -this.ClientRectangle.Height / 2); g.Transform = matricaTransformacija; g.DrawLine(new Pen(Color.FromArgb(255, 0, 0), 3), 0, 0, 100, 100); g.Restore(StanjePre); g.DrawLine(new Pen(Color.FromArgb(0, 255, 0), 3), 0, 0, 100, 100);

14. Color Color.FromArgb(255, 0, 0); Color.FromArgb(128, 255, 0, 0); Color.FromName("red"); Color.FromKnownColor(KnownColor.Red); Color.Red;

15. Pen

16. Pen // Create a new pen. Pen skyBluePen = new Pen(Brushes.DeepSkyBlue); // Set the pen's width. skyBluePen.Width = 8.0F; // Set the LineJoin property. skyBluePen.LineJoin = LineJoin.Bevel; // Draw a rectangle. e.Graphics.DrawRectangle(skyBluePen, new Rectangle(40, 40, 150, 200)); //Dispose of the pen. skyBluePen.Dispose();

17. LineCap – Start & End Olovka.StartCap = LineCap.DiamondAnchor; Olovka.EndCap = LineCap.Triangle; g.DrawLine(Olovka,50,500,500,500);

18. LineJoin Olovka.LineJoin = LineJoin.Bevel;

19. DashStyle  Olovka.DashStyle = DashStyle.DashDot; Pen Olovka = new Pen(Color.Black, 10);float[] NasaIsprekLinija =  {5.0f, 2.0f, 1.0f, 3.0f};Olovka.DashPattern =  NasaIsprekLinija;

20. Drawing basic shapes To draw lines with Windows GDI+ you need to create aGraphics object and a Pen object. The Graphics object provides the methods that actually do the drawing, and thePen object stores attributes of the line, such as color, width, and style.

21. Basic shapes • Lines • Rectangles • Ellipses • Arcs • Pies • Polygons • Cardinal Splines • BézierSplines • Paths • Open and Closed Curves • Regions • Clipping

22. Lines public void DrawLine(Pen pen, Point pt1, Point pt2 ); Pen Type: System.Drawing.PenPen that determines the color, width, and style of the line. Pt1 Type: System.Drawing.PointPoint structure that represents the first point to connect.   Pt2 Type: System.Drawing.PointPoint structure that represents the second point to connect. 

23. Lines g.DrawLine(new Pen(Color.Red, 3.2f), 0, 0, 250, 250); Point PocetnaTacka = new Point(0,0); Point KrajnjaTacka = new Point(250,50); Pen Olovka = new Pen(Color.GreenYellow, 3.2f); g.DrawLine(Olovka, PocetnaTacka, KrajnjaTacka);

24. Rectangles public void DrawRectangle( Pen pen, Rectangle rect ) Pen Type: System.Drawing.PenA Pen that determines the color, width, and style of the rectangle.  Rect Type: System.Drawing.RectangleA Rectangle structure that represents the rectangle to draw. 

25. Rectangles g.DrawRectangle(new Pen(Color.Blue, 2.5f), 50, 50, 150, 100); g.DrawRectangle(new Pen(Color.Blue, 2.5f), new Rectangle(50, 50, 100, 50));

26. Elipses public void DrawEllipse( Pen pen, Rectangle rect ) Pen Type: System.Drawing.PenA Pen that determines the color, width, and style of the rectangle.  Rect Type: System.Drawing.RectangleA Rectangle structure that represents the rectangle to draw. 

27. Ellipses g.DrawEllipse(new Pen(Color.Black, 3), 50, 50, 150, 100); g.DrawEllipse(new Pen(Color.Blue, 2.5f), new Rectangle(50, 50, 100, 50));

28. Arcs g.DrawArc(new Pen(Color.Black, 3), 50, 50, 150, 100, 0, 140);

29. Pies Graphics g = e.Graphics; MatrixmatricaTransformacija = new Matrix(1, 0, 0, -1, 0, 0); matricaTransformacija.Translate(this.ClientRectangle.Width / 2, -this.ClientRectangle.Height / 2); g.Transform = matricaTransformacija; g.DrawLine(new Pen(Color.Black), -this.ClientRectangle.Width / 2, 0, this.ClientRectangle.Width / 2, 0); g.DrawLine(new Pen(Color.Black), 0, this.ClientRectangle.Height / 2, 0, -this.ClientRectangle.Height / 2); Pen Olovka = new Pen(Color.FromName("red"), 3); g.DrawPie(Olovka, -100, -100, 200, 200, 0, 300);

30. Pies

31. Polygons Point [] tacke = new Point[] { new Point(100, 25), new Point(25, 100), new Point(150, 200), new Point(275, 100), new Point(200, 25)}; Pen Olovka = new Pen(Color.Black, 3); g.DrawPolygon(Olovka, tacke);

32. Cardinal & Bézier Splines

33. Bézier Splines

34. Paths • Paths are formed by combining lines, rectangles, and simple curves. • Lines • Rectangles • Ellipses • Arcs • Polygons • Cardinal splines • Bézier splines

35. Paths GraphicsPath gp = new GraphicsPath(FillMode.Alternate); //gp.AddPolygon(tacke); gp.AddLine(50, 150, 50, 350); gp.AddLine(50, 350, 250, 350); gp.AddArc(250, 250, 400, 200, 180, -180); gp.AddLine(650, 350, 850, 350); gp.AddLine(850, 350, 850, 150); gp.AddLine(850, 150, 650, 150); gp.Ad,dArc(250, 50, 400, 200, 0, -180); //gp.CloseFigure(); gp.AddLine(250, 150, 50, 150); gp.AddRectangle(new Rectangle(300, 200, 300, 100));

36. Paths g.FillPath(new SolidBrush(Color.Yellow), gp); g.DrawPath(Olovka, gp);

37. Brushes: • To fill a closed shape, you need aGraphics object and a Brushobject. • Solid Brushes • Hatch Brushes • Texture Brushes • Gradient Brushes

38. Solid Brushes public SolidBrush( Color color ) color Type: System.Drawing.ColorA Color structure that represents the color of this brush. 

39. Solid Brushes g.Clear(Color.Black); SolidBrush CetkaR = new SolidBrush(Color.FromArgb(128, 255, 0, 0)); SolidBrush CetkaG = new SolidBrush(Color.FromArgb(128, 0, 255, 0)); SolidBrush CetkaB = new SolidBrush(Color.FromArgb(128, 0, 0, 255)); g.FillEllipse(CetkaR, 50, 50, 300, 300); g.FillEllipse(CetkaG, 250, 50, 300, 300); g.FillEllipse(CetkaB, 150, 200, 300, 300);

40. Hatch Brushes public HatchBrush( HatchStylehatchstyle, Color foreColor, Color backColor ) hatchstyle Type: System.Drawing.Drawing2D.HatchStyleOne of the HatchStyle values that represents the pattern drawn by this HatchBrush.  foreColor Type: System.Drawing.ColorThe Color structure that represents the color of lines drawn by this HatchBrush.  backColor Type: System.Drawing.ColorThe Color structure that represents the color of spaces between the lines drawn by this HatchBrush. 

42. Hatch Brushes g.Clear(Color.White); HatchBrush Cetka = new HatchBrush(HatchStyle.Cross, Color.Green); HatchBrush Cetka1 = new HatchBrush(HatchStyle.Cross, Color.Black, Color.Red); HatchBrush Cetka2 = new HatchBrush(HatchStyle.Divot, Color.Yellow, Color.Blue); g.FillEllipse(Cetka, 50, 50, 300, 300); g.FillEllipse(Cetka1, 250, 50, 300, 300); g.FillEllipse(Cetka2, 150, 200, 300, 300);

43. Texture Brushes g.Clear(Color.White); Image slika = Image.FromFile("C:\\Documents and Settings\\Ognjen\\Desktop\\RG\\slike\\texture__.jpg"); Image slika1 = Image.FromFile("C:\\Documents and Settings\\Ognjen\\Desktop\\RG\\slike\\Y-YellowTexture.bmp"); Image slika2 = Image.FromFile("newwall.bmp"); TextureBrush Cetka = new TextureBrush(slika); TextureBrush Cetka1 = new TextureBrush(slika1); TextureBrush Cetka2 = new TextureBrush(slika2);