1. Essential Structures [Chapter-3]
Course : CSE-791 Advanced Windows Programming
Instructor : Dr. James Fawcett
Semester : Summer 2002
Presented By : Vivekananthan Murugesan & Minu Puranik

2. Topics Classes and Structures
Point [Two Dimensional Coordinate Points]
Size [Two-Dimensional Sizes in terms of Width & Height]
Rectangle
Color
Pens and Brushes
Paint Procedures
String Measurement

3. Classes & Structures C++
- Structure: All methods & fields are public by default
- Class: All methods & fields are private by default C#
- Structure: Value Type
- Class: Reference Type
- In both the types all methods, fields, events &
properties are private by default

4. Value Type Vs Reference Type
Question
Value Type
Reference Type
Allocation
Stack [Even though created using new – in case of struct]
Heap
Representation
Local Copies
Pointers to Memory Allocated
Base Type
Must derive from System.ValueType
Any other type. [Except: System.ValueType & Sealed]
Support Inheritance
NO [Always Sealed]
YES [if NOT sealed]
Parameter Passing
By Value [copy]
By Reference
Constructor Support
YES. But Default Constructors are reserved.
YES. [Of Course!]
Existence
Deleted when it falls out of the defined Scope
Until Garbage Collected
Example
int, float, bool, any struct
Form, any class

5. Value Type Vs Reference Type
CODE EXAMPLE
int a = 5
int b = a;
a = 10;
What is current value of b? b = 5
Form form1 = new Form();
Form form2 = form1;
form2.Text = “CSE 791”;
What is current value of form1.Text ? “CSE 791”

6. Point Point is a Number Pair (X , Y) - X : horizontal coordinate
- Y : vertical coordinate
- Generally represents a Point in a 2D Coordinate System
- Thus, X & Y can have positive and negative values +y +x -x
(0, 0) -y

7. Point […Continued] Point Constructor Type Example Point()
Point tempPt = new Point(); //[X=0, Y=0]
Point(int x, int y)
Point tempPt = new Point(5, 10); // [X=5, Y=10]
Point(int xypacked)
Point tempPt = new Point(0x ); // [X=16, Y=256]
Point(Size size)
Point tempPt = new Point(new Size(5, 10)); // [X=5, Y=10]
Special One
[Using Static Field]
Point tempPt =Point.Empty; // [X=0, Y=0]

8. Point […Continued] Point Creation Point tempPt; // WRONG!!!
Point tempPt = new Point(); // YES!
Point Properties
Type
Property
Accessibility
Example
int X
Get/Set
int x = tempPt.X; //[Get]
tempPt.X = 5; //[Set] Y
int y = tempPt.Y; //[Get]
tempPt.Y = 10; //[Set]
bool
IsEmpty
Get
bool flag = tempPt.IsEmpty; //[Get]

9. Point Public Interface Methods
Point […Continued]
Point Public Interface Methods
Method
Functionality
Type GetType()
Returns a Type object which fully describes object currently referenced [In Short: RTTI]
int GetHashCode()
Returns an integer which identifies a specific object instance
string ToString()
Returns the string representation of Object
Output Format: {X=0, Y=0}
Usage: Console.Write(tempPt.ToString());
bool Equals(Point)
Compares two Points [Both X & Y are compared separately]
Usage: bool isSame = tempPt1.Equals(tempPt2);
Usage: Bool isSame = tempPt1 == tempPt2;
Void Offset()
Adds given offset to the Point
Usage: tempPt.Offset(5,10); //tempPt.X+=5; tempPt.Y+=10;

10. Size Size is also a Number Pair (Width, Height)
- Similar to Point, but has Width & Height instead of X & Y
- Width & Height can have negative values.
[Mainly used for computations purpose]

11. Size […Continued] Size Constructor Type Example Size()
Size tempSz = new Size();
//[Width=0, Height=0]
Size(int width, int height)
Size tempSz = new Size(5, 10);
// [Width=5, Height=10]
Size(Point point)
Size tempSz = new Size(new Point(5,10));

12. Size Creation Size tempSz; // WRONG!!! Size Properties
Size tempSz = new Size(); // YES!
Size Properties
Type
Property
Accessibility
Example
int
Weight
Get/Set
int w = tempSz.Width; //[Get]
tempSz.Width = 5; //[Set]
Height
int h = tempSz.Height; //[Get]
tempSz.Height = 10; //[Set]
bool
IsEmpty
Get
bool flag = tempSz.IsEmpty; //[Get]

13. Point & Size Construction Casting Operations
Point tempPt = new Point(new Size(5, 10)); // [X=5, Y=10]
Size tempSz = new Size(new Point(5,10)); // [Width=5, Height=10]
Casting
tempPt = (Point)tempSz;
tempSz = (Size)tempPt;
Operations
tempSz3 = tempSz1 + tempSz2;
tempSz3 = tempSz1 – tempSz2;
tempSz1 += tempSz2;
tempSz1 -= tempSz2;
tempPt2 = tempPt1 + tempSz;
tempPt2 = tempPt1 – tempSz;
tempPt1 += tempSz;
tempPt1 -= tempSz;

14. PointF and SizeF Floating Point Representations of Point and Size
PointF: Similar to Point except X & Y are float values
SizeF: Similar to Size except Width & Height are float values
General Syntax:
- tempPtF.X = 5.5; //Error
- tempPtF.Y = 6.5; //Error
- tempPtF.X = (float)5.5; // OR tempPtF.X = 5.5f;
- tempPtF.Y = (float)6.5; // OR tempPtF.Y = 6.5f;

15. PointF and SizeF […Continued]
Constructor Comparison
Point
PointF
Size
SizeF ()
(x , y)
(Size)
(SizeF)
(Point)
(PointF)
(xyPacked)

16. PointF and SizeF […Continued]
Casting
To 
From
Point
PointF
Size
SizeF
YES NO

17. PointF and SizeF […Continued]
Point Static Methods
Name of Method
Functionality
Point Round(PointF ptF)
Rounds X & Y to nearest positive integer.
Point Truncate(PointF ptF)
Strips the fractional part and rounds towards next lowest integer.
Point Ceiling(PointF ptF)
Rounds towards next highest integer.

18. PointF and SizeF […Continued]
Size Static Methods
Name of Method
Functionality
Size Round(SizeF ptF)
Rounds Width & Height to nearest positive integer.
Size Truncate(SizeF ptF)
Strips the fractional part and rounds towards next lowest integer.
Size Ceiling(SizeF ptF)
Rounds towards next highest integer.
SizeF Instance Methods
Name of Method
Functionality
PointF ToPointF()
Converts SizeF to PointF.
Size ToSize()
Equivalent to Truncate().

19. Rectangle
“Rectangle” structure defines a rectangle as a combination of a Point and a Size
Point refers to the location of the upper left corner of the rectangle and Size is the Width and Height of this Rectangle.
Size should be Non-Negative. [No specific Restriction]
Constructors
Rectangle(Point pt, Size size)
Rectangle(int x, int y, int width, int height)

20. RectangeF Constructors
RectangleF is similar to Rectangle except that the data types associated with RectangleF are float, PointF and SizeF rather than int, Point and size.
Constructors
RectangleF(PointF ptf, SizeF sizef)
RectangleF(float x, float y, float width, float height)

21. Rectangle & RectangleF
Rectangle Static Methods
Rectangle Round(RectangleF rectF)
Rectangle Truncate(RectangleF rectF)
Rectangle Ceiling(RectangleF rectF)
Rectangle/RectangleF ToString Method
Output Format: {X=0, Y=0, Width=0, Height=0}
Note:
RectangleF is similar to Rectangle except that the data types associated with RectangleF are float, PointF and SizeF rather than int, Point and size. Hence following slides refer to Rectangle which are also applicable to RectangleF.

22. Rectangle […Continued]
Rectangle Properties
Type
Property
Accessibility
Point
Location
Get/Set
Size
int X Y
Width
Height
Left
Get
Int
Top
Right
Bottom
Bool
IsEmpty

23. Rectangle […Continued]
Comparing Two Rectangles
Equality Operator [==]
Inequality Operator [!=]
Equals Method
Creating Rectanlges [Old Way]
static Rectangle FromLTRB(int xLeft, int yTop, int xRight, int yBottom

24. Rectangle […Continued]
Offset and Inflate Methods
void Offset(int x, int y)
void Offset(Point pt)
void Inflate(int x, int y)
static Rectangle Inflate(Rectangle rect, int x, int y)
rect.Offset(x,y) is equivalent to:
rect.X+=x;
rect.Y+=y
rect.Inflate(x,y) is equivalent to:
rect.X-=x5;
rect.Y-=y;
rect.Width +=2*x;
rect.Height +=2*y;

25. Rectangle […Continued]
More Rectangle Methods
static Rectangle Union(Rectangle rect1, Rectangle rect2)
static Rectangle Intersect(Rectangle rect1, Rectangle rect2)
void Intersect(Rectangle rect)
bool Contains(Point)
bool Contains(int x, int y)
bool Contains(Rectangle rect)
bool IntersectsWith(Rectangle rect)

26. Form Properties/Events
- Form class has 14 Properties. [11 inherited from Control]
Form(Control) Properties (selection)
Type
Property
Accessibility
Comments
Point
Location
Get/Set
Location relative to Screen
Size
Size of Full Form
Rectangle
Bounds
Equals Rectangle(Location, Size)
int
Width
Equals Size.Width
Height
Equals Size.Height
Left
Equals Location.X
Top
Equals Location.Y
Right
Get
Equals Location.X + Size.Width
Bottom
Equals Location.Y + Size.Height

27. Form Properties/Events
DON’T DO
- Size.Width =2; //Accessing Property of Property
Form Properties (selection)
Type
Property
Accessibility
Comments
Point
DesktopLocation
Get/Set
Location relative to Screen, taking windows taskbar into account
Rectangle
DesktopBounds
Size of Full Form taking windows taskbar into account

28. Form Properties/Events
Form(Control) Properties (selection)
- Client Area Excludes:
Caption Bar, Border, Menu, ScrollBar
Type
Property
Accessibility
Comments
Size
ClientSize
Get/Set
Size of ClientArea
Rectangle
ClientRectangle
Get
No Additional Information! X=0; Y=0; But useful for passing as parameter to Rectangle parameter.
See: FormSize Demo

29. Form Properties/Events
Control Events (Selection)
Control Invalidate Methods
Event
Method
Delegate
Argument
Move
OnMove
EventHandler
EventArgs
Resize
OnResize
void Invalidate()
void Invalidate(Rectangle rect)
void Invalidate(bool IncludeChildren)
void Invalidate(Rectangle rect, bool IncludeChildren)
void Invalidate(Region regn)
void Invalidate(Region regn, bool IncludeChildrren)

30. Form Properties/Events
Invalidate()
- Informs the Windows that client are is no longer valid
and to be repainted.
- causes a call to OnPaint
- OnPaint call doesn’t occur right away
- all pending requests will be served first
- To Update the client area immediately follow the
invalidate call with a call to Control Object’s Update
method.
void Update();

31. Color Structure
Color in Windows Forms is based on ARGB(a;pha-red-green-blue) model
alpha channel determines the transparency of the color. It ranges from 0 for transparent to 0xFF for opaque.
Construction:
Color color = new Color(); //creates a transparent black color
//only default constructor is supported

32. Color Structure Static Color Properties
- Provide 140 Colors [HTML Standard] to choose from.
- 141st property, named Transparent, represents a
transparent color
Type
Property
Accessibility
Color
AliceBlue
Get
AntiqueWhite …
YellowGreen
Transparent

33. Color Structure Color.FromArgb Static Methods
- To create create colors based on red, green, blue and alpha components, you can use the following Color.FromArgb static methods.
Color Color.FromArgb(int r, int g, int b)
Color Color.FromArgb(int a, int r, int g, int b)
Color Color.FromArgb(int a, Color color)
Color Color.FromArgb(int argbPacked)

34. Pens and Brushes Pen Object is used for drawing lines or curves
Brush Object is used for drawing filled areas and text
Pens and Brushes themselves are specified using Color, but other characteristics are often involved as well.
Constructing Pen
1. Pen mypen = new Pen(new Color());
2. Pen mypen = new Pen(Color.Red)
3. Pen mypen = Pens.Red //Pens has 141 static properties
More Descriptions about Pen on chapter 17!

35. Pens and Brushes Brush:
- Brush class itself is abstract, which means you can’t create instance of it
- Brush is parent class for 5 other classes. SolidBrush, HatchBrush, TextureBrush, LinearGradientBrush and PathGradientBrush.
Brush Construction:
1. Brush mybrush = new SolidBrush(new Color());
2. Brush mybrush = new SolidBrush(Color.Red);
3. Brush mybrush =Brushes.Red //Brushes has 141 static properties
More Descriptions about Brushes on chapter 17!

36. System Colors Also called “User-Preference Colors”
Colors set by the users for the Windows Environment using Display Properties
Windows maintains 29 colors for the user interface out of which 26 are available in the Windows Forms Framework.
One can obtain these colors from SystemColors class, which consists of 26 read-only properties, each of which returns a Color Object.
Type
Property
Accessibility
Comments
Color
ActiveBorder
Get
Border of Active Window
ActiveCaption
Caption Bar of Active Window …
ControlText
Text Color of Controls
Desktop
Windows Desktop Color
WindowText
Window Text

37. Pens and Brushes Creating Pens and Brushes using SystemColors:
- Pen mypen = new Pen(SystemColor.Desktop);
- Brush mybrush = new SolidBrush(SystemColor.Desktop);
SystemPens:
- has 15 static read only properties that return object of type Pen
Type
Property
Accessibility
Pen
ActiveCaptionText
Get
Control …
WindowText

38. Pens and Brushes SystemBrushes:
- has 21 static read only properties that return object of type Brush
Type
Property
Accessibility
Brush
ActiveBorder
Get
ActiveCaption …
WindowText

39. Pens & Brushes More Ways to Create:
Pen mypen = SystemPens.FromSystemColor(SystemColor.ActiveBorder);
Brush mybrush = SystemBrushes.FromSystemColor(SystemColor.MenuText);
Known Colors:
KnownColor is an Enumeration that encompasses all the color names and all the system colors

40. Form Examples RandomClear Example: RandomClearResizeRedraw Example:
- Clears the Form with different colors selected at random.
- Clear is restricted to the region that’s newly invalid. thus entire form is not repainted.
RandomClearResizeRedraw Example:
- 1 way for complete Clear: override OnResize and Put a invalidate call.
- Another way is set the ResizeRedraw property to true.

41. StringFormat Used to Change the default text alignment Properties:
StringAlignment Enumeration:
Type
Property
Accessibility
Comments
StringAlignment
Alignment
Get/Set
Horizontal alignment
Color
LineAlignment
Vertical Alignment
Member
Value
Description
Near
Usually left or top
Center 1
Always Center
Far 2
Usually right or bottom
More Descriptions about StringFormat on chapter 9!

42. Form Examples FourCorners Example - Using StringFormat to display Text
HelloCenteredAlignment Example
HelloCenteredMeasured Example
- Using SizeF sizeText = grfx.MeasueString(str, font);
More Descriptions about MeasueString on chapter 9!

43. Form Examples HelloCenteredRectangle Example HuckleberryFinn Example
- Using
void DrawString(string str, Font f, Brush b, Rectangle rect, Stringformat strfmt)
HuckleberryFinn Example
void DrawString(string str, Font f, Brush b, Rectangle rect)

44. Reference Programming Microsoft Windows with C# - Charles Petzold
C# and the .Net Platform
- Andrew Troelsen