Chapter2: Drawing a Window

Drawing with the GDI

3 Drawing Functions of CDC (1/3) Point Same with the SetPixel, but it does not return the original color value. So it is more efficient. SetPixelV Set the given color value at the position and return the original color value at the position SetPixel Get the color value at the given position.GetPixel Descriptionfunction COLORREF color = dc.GetPixel (x,y); dc.SetPixelV(x,y, RGB(r,g,b)); COLORREF color = dc.GetPixel (x,y); dc.SetPixelV(x,y, RGB(r,g,b));

4 COLORREF A data type for storing a color value 32 bit as 0x00rrggbb Macro function easy to use: COLORREF color = RGB(r,g,b); r = GetRValue (color); g = GetGValue (color); b = GetBValue (color); COLORREF color = RGB(r,g,b); r = GetRValue (color); g = GetGValue (color); b = GetBValue (color);

Drawing test:

6 Drawing Functions of CDC (2/3) Drawing shapes dc.Rectangle (x1, y1, x2, y2); dc.Ellipse (x1, y1, x2, y2); (x1, y1) (x2, y2) FunctionDescription Rectangle()Drawing a rectangle Ellipse()Drawing an ellipse

void GetClientRect(CRect) How to get the window size? CRect : a class for storing a rectangle information –member variables: bottom top right left CRect rect; GetClientRect(rect); CRect rect; GetClientRect(rect); (left, top) (right, top) (right, bottom)(left, bottom) msdn2.microsoft.com/ko-kr/library/zzs00fs6(VS.80 ).aspx

void GetClientRect(CRect) Practice: draw an ellipse fit to the client area CRect rect; GetClientRect(rect); CRect rect; GetClientRect(rect);

More shapes of CDC (2/3) FunctionDescription ChordDraws a closed figure bounded by the intersection of an ellipse and a line EllipseDraws a circle or an ellipse PieDraws a pie-shaped wedge PolygonConnects a set of points to form a polygon RectangleDraws a rectangle with square corners RoundRectDraws a rectangle with rounded corners

10 Drawing Functions of CDC (3/3) Drawing a Line Drawing a line from the original position to the given position LineTo() Move your pen to the given positionMoveTo() Descriptionfunction dc.MoveTo(x1,y1); dc.LineTo(x2,y2); dc.MoveTo(x1,y1); dc.LineTo(x2,y2); (x1,y1) (x2,y2)

Coding practice

More line functions(3/3) FunctionDescription MoveTo Sets the current position in preparation for drawing LineTo Draws a line from the current position to a specified position and moves the current position to the end of the line Polyline Connects a set of points with line segments PolylineTo Connects a set of points with line segments beginning with the current position and moves the current position to the end of the polyline Arc Draws an arc ArcTo Draws an arc and moves the current position to the end of the arc PolyBezier Draws one or more Bézier splines PolyBezierTo Draws one or more Bézier splines and moves the current position to the end of the final spline PolyDraw Draws a series of line segments and Bézier splines through a set of points and moves the current position to the end of the final line segment or spline

13 Drawing a Text by using CDC Text-related functions Sets alignment parametersSetTextAlign() Sets the background colorSetBkColor() Sets the text output colorSetTextColor() Draws text in a formatting rectangleDrawText() Outputs a line of test at the positionTextOut() DescriptionFunction Name dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(0,255,0)); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,_T(“Sejong University”)); dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(0,255,0)); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,_T(“Sejong University”));

Coding Test CRect rect; GetClientRect(rect); dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(255,255,0)); dc.DrawText(CString(_T("Draw Text Test")), &rect, DT_CENTER|DT_VCENTER|DT_SINGLELINE); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,CString(_T("Welcome"))); CRect rect; GetClientRect(rect); dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(255,255,0)); dc.DrawText(CString(_T("Draw Text Test")), &rect, DT_CENTER|DT_VCENTER|DT_SINGLELINE); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,CString(_T("Welcome")));

Coding Test CRect rect; GetClientRect(rect); dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(255,255,0)); dc.DrawText(CString(_T(“Draw Text Test”)), &rect, DT_CENTER|DT_VCENTER|DT_SINGLELINE); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,CString(_T("Welcome“))); CRect rect; GetClientRect(rect); dc.SetTextColor(RGB(255,0,0)); dc.SetBkColor(RGB(255,255,0)); dc.DrawText(CString(_T(“Draw Text Test”)), &rect, DT_CENTER|DT_VCENTER|DT_SINGLELINE); dc.SetTextAlign(TA_CENTER); dc.TextOut(300,200,CString(_T("Welcome“))); Output text The text will be placed in the rectangle Text Alignment xy Output text

Text Color related functions AttributeDefault Text colorblack Background Color white Background color mode OPAQUE  TRANSPARE NT Get with GetTextColor() GetBkColor() GetBkMode() Set with SetTextColor() SetBkColor() SetBkMode()

Drawing with GDI An Initial Rectangle: How to change the color and attributes? –Changing the Pen : LINE –Changing the Brush : FACE

18 GDI Objects (1/3) GDI Objects (class) –Tools for drawing with the GDI –Changing the attributes of the shapes toolusageClass name penWhen drawing a lineCPen brushWhen filling a regionCBrush fontWhen printing out a textCFont bitmapWhen filling a region with an imageCBitmap regionWhen defining a polygonal regionCRgn

19 GDI Objects(2/3) Class hierarchy

20 GDI Objects (3/3) When you draw an image (in real world): 1.Choosing a pen 2.Grabbing the pen 3.Drawing an image 4.Releasing the pen

21 GDI Objects (3/3) When you draw an image (by using GDI) 1.Defining a tool (pen) 2.Assigning the tool to the DC (CDC::SelectObject()) 3.Drawing an image 4.(Releasing the tool from the DC)

22 CPen (1/2) How to use: Pen Style // method 1 CPen pen(PS_SOLID, 2, RGB(255, 0, 0)); // using constructor // or method 2 CPen pen; pen.CreatePen (PS_SOLID, 2, RGB (255, 0, 0)); // using initializer Stylewidthcolor

CPen (2/2) Coding Example CPaintDC dc(this); CPen pen(PS_SOLID, 1, RGB(0, 0, 255)); dc.SelectObject(&pen); dc.Rectangle(100, 100, 200, 200); CPaintDC dc(this); CPen pen(PS_SOLID, 1, RGB(0, 0, 255)); dc.SelectObject(&pen); dc.Rectangle(100, 100, 200, 200);

24 CBrush (1/2) A Brush defines how to fill a region Different kinds of the brush (by using different constructor) Various BrushesExample Solid brush: filling with a color CBrush brush(RGB(255, 0, 0)); Hatch brush: filling with a pattern CBrush brush(HS_DIAGCROSS, RGB(255, 0, 0)); Bitmap brush: filling with an image CBitmap bitmap; bitmap.LoadBitmap(IDB_BITMAP1); CBrush brush(&bitmap);

CBrush (2/2) Coding Example CPaintDC dc(this); CBrush brush(RGB(255, 0, 0)); dc.SelectObject(&brush); dc.Ellipse(100, 100, 200, 200); CPaintDC dc(this); CBrush brush(RGB(255, 0, 0)); dc.SelectObject(&brush); dc.Ellipse(100, 100, 200, 200); CPaintDC dc(this); CBrush brush(HS_DIAGCROSS, RGB(255, 0, 0)); dc.SelectObject(&brush); dc.Ellipse(100, 100, 200, 200); CPaintDC dc(this); CBrush brush(HS_DIAGCROSS, RGB(255, 0, 0)); dc.SelectObject(&brush); dc.Ellipse(100, 100, 200, 200);

26 CFont (1/2) How to use 1.Create a CFont variable 2.Call CreateFont() function CFont font; font.CreateFont(...); // font.CreateFontIndirect(...); // font.CreatePointFont(...); // font.CreatePointFontIndirect(...); CFont font; font.CreateFont(...); // font.CreateFontIndirect(...); // font.CreatePointFont(...); // font.CreatePointFontIndirect(...);

27 CFont (2/2) Coding Example CPaintDC dc(this); CFont font; font.CreatePointFont(400, _T("Arial")); dc.SelectObject(&font); dc.TextOut(10, 10, _T("Hello")); CPaintDC dc(this); CFont font; font.CreatePointFont(400, _T("Arial")); dc.SelectObject(&font); dc.TextOut(10, 10, _T("Hello")); SizeFont name

28 Predefined Objects (stock objects) –Call CDC::SelectStockObject(…) fucntion namemeaning BLACK_PENblack pen with 1 pixel width WHITE_PENwhite pen with 1 pixel width NULL_PENtransparent pen with 1 pixel width BLACK_BRUSHblack solid brush DKGRAY_BRUSHdark gray brush GRAY_BRUSHgray brush LTGRAY_BRUSHlight gray brush HOLLOW_BRUSH or NULL_BRUSH transparent brush SYSTEM_FONTdefault font used by windows system ex) menu, dialog box