Mapping Modes

8/9/2019 Mapping Modes

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VISUAL PROGRAMMING


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COLORS


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COLOR

- one the most fundamental objects that enhances the aesthetic

appearance of an object

- non-spatial object that is added to an object to modify some of

its visual aspects

-Three numeric values are used to create a color

Red

Green

Blue


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COLOR

- Each one represented in 8-bits and the value for each color

ranges from 0-255

- These 3 colors can be combined to form other colors

- Using these 3 we can create approximately 16 million colors

(255*255*255=16581375)


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COLOR

- computer monitor has a surface that resembles a series of tiny

horizontal and vertical lines

- intersection of a one horizontal line and a vertical line is called a

pixel that holds, carries, or displays one color

- As the pixels close to each other have different colors, the effect

is a wonderful distortion that creates an aesthetic picture


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- After declaring initialize it with a 32-bit numeric value.It can be

done as follows

COLORREF NewColor = 16711935;

- Although the above number is a legitimate color value it doesnot mean much

- One macro is defined to create a color called RGB macro. Its

syntax is

COLORREF RGB(BYTE byRed, BYTE byGreen, BYTE

byBlue);


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RGB MACRO

- The RGB macro behaves like a function and allows you to pass

three numeric values separated by a comma.

- Each value must be between 0 and 255

- Initialization can be done as follows

COLORREF NewColor = RGB(255, 0, 255);


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COLORING A PIXEL

- A pixel is the real object that holds a color

-The pixels are stored in an array of [x][y] value. To change thecolor of a pixel, you can call the CDC::SetPixel() method

- Its syntaxes are:

COLORREF SetPixel(int x, int y, COLORREF crColor);

COLORREF SetPixel(POINT point, COLORREF crColor);


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FONTS


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FONT

- A list of symbols that can be drawn on a device context to

produce a readable message

- FONT CREATION

- FONT SELECTION


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FONT CREATION

- Font is created as a variable of the CFont class which is based

on the CGdiObject

- To declare aC

Font variable use the default constructor asfollows

CFont NewFont;

- After declaring a CFont variable, you must initialize it. Callingone of the Create member functions can do


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- There are three class methods used for creating fonts

CreatePointFont

CreateFont CreateFontIndirect


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CreatePointFont Method

- Its syntax is

BOOL CreatePointFont(int nPointSize, LPCTSTR

lpszFaceName, CDC* pDC= NULL);

Where nPointSize is the height of the font

lpszFaceName is the name of the font or NULL


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void myframe::

OnLButtonDown(UINTnFlags,CPoint point)

{

CFont font;

CClientDC pDC(this);

font.CreatePointFont(920, "Arial");pDC.SelectObject(&font);

pDC.SetTextColor(RGB(0, 125, 250));

pDC.TextOut(20, 18, "Hello", 5);

}


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CreateFont Method

- Its syntax is

BOOL CreateFont( int nHeight,

int nWidth,

int nEscapement,

int nOrientation,

int nWeight,BYTE bItalic,

BYTE bUnderline,

BYTE cStrikeOut,

BYTE nCharSet,

BYTE nOutPrecision,

BYTE nClipPrecision,

BYTE nQuality,BYTE nPitchAndFamily,

LPCTSTRlpszFacename);


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CreateFont Method

- nHeight- height applied to the text.

- nWidth - desired width that will be applied on the text.

- nEscapement- angle used to orient the text (orientedcounterclockwise)

- nOrientation -angular orientation of the text with regards to thehorizontal axis.

- nWeight-Font weight

- bItalic specifies whether the font will be italicized (TRUE) ornot (FALSE).

- bUnderline is used to underline (TRUE) or not underline(FALSE) the text.

- cStrikeOutis specifies whether the text should be stroke out(TRUE) or not (FALSE) with a line.


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CreateFont Method

- nCharSet specifies the character set used

- nOutPrecision - amount precision used to evaluate the numeric

values used on this function for the height, the width, and angles

-nClipPrecisionamount ofclipping

-nQuality specifies how the function will attempt to match the

font's characteristics

-nPitchAndFamily specifies the category of the font used

-lpszFacename is the name of the font used


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void myframe::OnLButtonDown(UINT nFlags,CPoint

point)

{

CFont font;

font.CreateFont(46, 28, 215, 0,FW_NORMAL, FALSE,

FALSE, FALSE,ANSI_C HARSET,

OUT_DEFAULT_PRECIS,

CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY,

DEFAULT_PITC

H | FF_ROMAN, "Times NewRoman");

pDC->SelectObject(&font);

pDC->TextOut(20, 128, Hello", 5);

}


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CreateFontIndirect Method

-Its syntax is

BOOL CreateFontIndirect(const LOGFONT* lpLogFont);

- LOGFONT structure is used to define all the characteristics of

the font


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void myframe::OnLButtonDown(UINT nFlags,CPoint

point)

{ CClientDC pDC(this);

CFont font;

LOGFONT LogFont;

LogFont.lfStrikeOut = 0;

LogFont.lfUnderline = 0;

LogFont.lfHeight = 42;

LogFont.lfEscapement = 0;

LogFont.lfItalic = TRUE;

font.CreateFontIndirect(&LogFont);

pDC.SelectObject(&font);pDC.TextOut(20, 18, Hello", 5);

}


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MAPPING MODES


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DEFAULT COORDINATE SYSTEM

- The coordinates of the drawing area are located on

the upper-left corner of the screen.

- The horizontal axis moves from (0,0) to the right and

the vertical axis moves from (0,0) down

- For example, consider the code for creating anellipse

0,0+X

+Y


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DEFAULT COORDINATE SYSTEM

void CExoDraw1View::OnPaint()

{

CPaintDC dc(this); // device context for painting// A circle whose center is at the origin (0, 0)dc.Ellipse(-50, -50, 50, 50);

// A line that starts at (0, 0) and ends at (100, 100)dc.MoveTo(0, 0);

dc.LineTo(100, 100);}

- The output of this is shown in the figure as follows


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CHANGING COORDINATE SYSTEM

- The MFC provides various functions to deal with the coordinatespositions and extents of the drawing area .

- One such function is the CDC::SetViewportOrg(). The syntaxes ofthis method are

SetViewportOrg(int X, int Y);

SetViewportOrg(CPoint Pt);

- The function of this method is to change the origin of thecoordinate system


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CHANGING COORDINATE SYSTEM

- To see the effect of this method change the previous OnPaint()

method as follows


{

CPaintDC dc(this); // device context for paintingdc.SetViewportOrg(200, 150);

// A circle whose center is at the origin (0, 0)dc.Ellipse(-50, -50, 50, 50);

// A line that starts at (0, 0) and ends at (100, 100)dc.MoveTo(0, 0);

dc.LineTo(100, 100);

}


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MAP MODES

- To control the orientation of the axes of the device context , amethod called SetMapMode() is used.

- The syntax of this method is

int SetMapMode(int nMapMode);

- It performs two functions

-> controls the orientation of the coordinate system

-> helps with the unit system you would prefer to use.


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MM_TEXT

- Default map mode

- With this map mode the dimensions or measurements specified inthe CDC methods are kept as it is.

- horizontal axis moves from (0, 0) to the right and the vertical axis

moves from (0, 0) down

- In general, no change is made to both the orientation and the

measurement units.


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MM_TEXT

void CExoDraw1View::OnPaint() {

CPaintDC dc(this); // device context for painting

dc.SetMapMode(MM_TEXT);

dc.SetViewportOrg(380, 220);

CPen PenRed(PS_SOLID, 1, RGB(255, 0, 0));dc.SelectObject(PenRed);

dc.Ellipse(-100, -100, 100, 100);

CPen PenBlue(PS_SOLID, 1, RGB(0, 0, 255));

dc.SelectObject(PenBlue);

dc.MoveTo(-380, 0); dc.LineTo(380, 0);dc.MoveTo(0, -220); dc.LineTo(0, 220);

CPen PenOrange(PS_SOLID, 1, RGB(255, 128, 0));

dc.SelectObject(PenOrange);

// A diagonal line at 45 degrees

dc.MoveTo(0, 0); dc.LineTo(120, 120); }


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MM_TEXT


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MM_LOENGLISH

- It performs two actions

* It changes the orientation of the vertical axis: the positivey axis would move from (0, 0) up

* Each unit of measure provided is divided by 100

(unit/100)

- If we change the map mode in the previous code to

MM_LOENGLISH the output will look as follows

0,0 +X

+Y


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MM_HIENGLISH

- It sets the orientation so the vertical axis moves from (0, 0)

- Each unit is divided by 1000 (1/1000 = 1000th

) that is significantand can change the display of a drawing

- Now the output will look as follows


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MM_HIENGLISH


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MM_LOMETRIC & MM_HIMETRIC

- uses the same axes orientation as the previous two modes

- With MM_LOMETRIC map mode each unit is reduced by 10%

- With MM_HIMETRIC map mode each unit is multiplied with

0.01mm.

- The example program using these modes are shown in following

figures.


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MM_LOMETRIC


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MM_HIMETRIC


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MM_TWIPS

- The MM_TWIPS map mode divides each logical unit by 20

- Actually a twip is equivalent to 1/1440 inch


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MM_TWIPS


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CUSTOMIZING THE UNIT AND

COORDINATE SYSTEM

- To control the unit system & the orientation of the axes two

map modes are used. They are

MM_ISOTROPHIC

MM_ANISOTROPHIC

- With MM_ISOTROPHIC , one unit in the horizontal axis is

equivalent to one unit in the vertical axis

- With MM_ANISOTROPHIC, the units should be converted on

each individual axis

- One more method used to change the unit system isSetWindowExt() that specifies how much each new unit will bemultiplied by the old or default unit system


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MM_ISOTROPHIC

- The syntaxes of this method are

CSize SetWindowExt(int cx, int cy);

CSize SetWindowExt(SIZE size);

- The following example shows the effect of this method


{

CPaintDC dc(this); // device context for paintingdc.SetMapMode(MM_ISOTROPIC);

dc.SetViewportOrg(340, 220);dc.SetWindowExt(480, 480);

. Same as previous

}


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Without Using MM_ISOTROPHIC


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THANK YOU

Documents

Mapping Modes