C graphics basic

8/8/2019 C graphics basic

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Pixel:Pixel is otherwise called as picture elements. These are nothing but small dots.

Using these tiny dots or in other words pixels images especially graphics images are

built on screen.

If all pictures are built by concept of pixel then wondering how each picture differ

that is how some picture appear more brighter while some other have a shadyeffect. All this is by the concept or technically terminology called as resolution.

Resolution:Resolution is the number of rows that appear from top to bottom of a screenand in turn the number of pixels or pixel elements that appear from left toright on each scan line. Based on this resolution only the effect of pictureappears on screen.

In other words greater the resolution greater will be the clarity of picture.This is because greater the number of dots greater will be sharpness of

picture. That is resolution value is directly proportional to clarity of picture.

Modes:There are generally two modes available in C namely text mode andgraphics mode.

Text mode:Text mode is a kind of computer display mode in which the content of the screen isinternally represented in terms of textual characters rather than individual pixels.

Typically, the screen consists of a uniform grid ofcharacter cells, each of whichcontains one of the characters of the character set.

Text mode applications communicate with the user with command-lineinterfaces and text user interfaces. The advantages of text modes comparedto graphics modes include lower memory consumption and faster screenmanipulation.

Also, text mode applications have relatively low bandwidth requirements inremote terminal use. An obvious disadvantage of text mode is the restrictedscreen content, which makes text mode impractical for many types ofapplications.

Graphics mode:In a graphics mode we have generally the following adapters namelyCGA (Color Graphics Adapter) [640x200, 4 bit 2 colors]EGA (Enhanced Graphics Adapter) [640x350, 4 bit 16 colors]VGA(Video Graphics Adapter) [ 640x480, 4 bit 16 colors]

Each adapter differs in the way of generating colors and also in the numberof colors produced by each adapter. Pixel being a picture element when weconsider the graphics mode each pixel has a color associated with it. But the

Prepared By: Jaydev Gajera
http://en.wikipedia.org/wiki/Pixelhttp://en.wikipedia.org/wiki/Character_(computing)http://en.wikipedia.org/wiki/Character_sethttp://en.wikipedia.org/wiki/Command-line_interfacehttp://en.wikipedia.org/wiki/Command-line_interfacehttp://en.wikipedia.org/wiki/Text_user_interfacehttp://en.wikipedia.org/wiki/Pixelhttp://en.wikipedia.org/wiki/Character_(computing)http://en.wikipedia.org/wiki/Character_sethttp://en.wikipedia.org/wiki/Command-line_interfacehttp://en.wikipedia.org/wiki/Command-line_interfacehttp://en.wikipedia.org/wiki/Text_user_interface


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way these colors are used depends on adapters because each adapter differsin the way they handle colors and also in the number of colors supported.There are numerous graphics functions available in c.

For example:Function: putpixel(x, y, color)Purpose: The functionality of this function is it put a pixel or in other words a dotat position x, y given in inputted argument. Here one must understand that thewhole screen is imagined as a graph. In other words the pixel at the top left handcorner of the screen represents the value (0, 0).Here the color is the integer value associated with colors and when specifiedthe picture element or the dot is placed with the appropriate color associatedwith that integer value.

Two Dimensional Coordinate System

1. Rectangle Coordinate SystemThis system commonly known as Cartesian coordinate system.

A Cartesian coordinate system specifies each point uniquely in a plane bya pair ofnumericalcoordinates, which are the signed distances from thepoint to two fixed perpendicular directed lines, measured in the same unit oflength.

Each reference line is called a coordinate axis or just axis of the system,and the point where they meet is its origin.

The coordinates can also be defined as the positions of the perpendicularprojections of the point onto the two axes, expressed as a signed distancesfrom the origin.

http://en.wikipedia.org/wiki/Point_(geometry)http://en.wikipedia.org/wiki/Plane_(mathematics)http://en.wikipedia.org/wiki/Numberhttp://en.wikipedia.org/wiki/Positive_and_negative_numbershttp://en.wikipedia.org/wiki/Perpendicularhttp://en.wikipedia.org/wiki/Unit_lengthhttp://en.wikipedia.org/wiki/Unit_lengthhttp://en.wikipedia.org/wiki/Orthogonal_projectionhttp://en.wikipedia.org/wiki/Orthogonal_projectionhttp://en.wikipedia.org/wiki/Point_(geometry)http://en.wikipedia.org/wiki/Plane_(mathematics)http://en.wikipedia.org/wiki/Numberhttp://en.wikipedia.org/wiki/Positive_and_negative_numbershttp://en.wikipedia.org/wiki/Perpendicularhttp://en.wikipedia.org/wiki/Unit_lengthhttp://en.wikipedia.org/wiki/Unit_lengthhttp://en.wikipedia.org/wiki/Orthogonal_projectionhttp://en.wikipedia.org/wiki/Orthogonal_projection


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Illustration of a Cartesian coordinate plane. Four points are marked and labeled withtheir coordinates: (2,3) in green, (3,1) in red, (1.5,2.5) in blue, and the origin(0,0) in purple.Choosing a Cartesian coordinate system for a plane means choosing an ordered pairof lines (axes) at right angles to each other, a single unit of length for both axes,and an orientation for each axis. The point where the axes meet is taken as theorigin for both axes, thus turning each axis into a number line. Each coordinate of apointp is obtained by drawing a line throughp perpendicular to the associated axis,finding the point q where that line meets the axis, and interpreting q as a number of

that number line.

Cartesian coordinates are the foundation ofanalytic geometry, and provideenlightening geometric interpretations for many other branches ofmathematics, such as linear algebra, complex analysis, differentialgeometry, multivariate calculus, group theory, and more.

A familiar example is the concept of the graph of a function. Cartesiancoordinates are also essential tools for most applied disciplines that deal withgeometry, including astronomy, physics, engineering, and many more. Theyare the most common coordinate system used in computer graphics,

computer-aided geometric design, and other geometry-related dataprocessing.

2. Polar Coordinate SystemIn mathematics, the polar coordinate system is a two-dimensionalcoordinate

system in which each point on a plane is determined by a distance from a fixed

point and an angle from a fixed direction.

http://en.wikipedia.org/wiki/Ordered_pairhttp://en.wikipedia.org/wiki/Right_anglehttp://en.wikipedia.org/wiki/Analytic_geometryhttp://en.wikipedia.org/wiki/Linear_algebrahttp://en.wikipedia.org/wiki/Complex_numberhttp://en.wikipedia.org/wiki/Differential_geometryhttp://en.wikipedia.org/wiki/Differential_geometryhttp://en.wikipedia.org/wiki/Calculushttp://en.wikipedia.org/wiki/Group_theoryhttp://en.wikipedia.org/wiki/Graph_(mathematics)http://en.wikipedia.org/wiki/Function_(mathematics)http://en.wikipedia.org/wiki/Astronomyhttp://en.wikipedia.org/wiki/Physicshttp://en.wikipedia.org/wiki/Engineeringhttp://en.wikipedia.org/wiki/Computer_graphicshttp://en.wikipedia.org/wiki/Computer-aided_geometric_designhttp://en.wikipedia.org/wiki/Computational_geometryhttp://en.wikipedia.org/wiki/Computational_geometryhttp://en.wikipedia.org/wiki/Mathematicshttp://en.wikipedia.org/wiki/Dimensionhttp://en.wikipedia.org/wiki/Coordinate_systemhttp://en.wikipedia.org/wiki/Coordinate_systemhttp://en.wikipedia.org/wiki/Point_(mathematics)http://en.wikipedia.org/wiki/Plane_(mathematics)http://en.wikipedia.org/wiki/Distancehttp://en.wikipedia.org/wiki/Anglehttp://en.wikipedia.org/wiki/Ordered_pairhttp://en.wikipedia.org/wiki/Right_anglehttp://en.wikipedia.org/wiki/Analytic_geometryhttp://en.wikipedia.org/wiki/Linear_algebrahttp://en.wikipedia.org/wiki/Complex_numberhttp://en.wikipedia.org/wiki/Differential_geometryhttp://en.wikipedia.org/wiki/Differential_geometryhttp://en.wikipedia.org/wiki/Calculushttp://en.wikipedia.org/wiki/Group_theoryhttp://en.wikipedia.org/wiki/Graph_(mathematics)http://en.wikipedia.org/wiki/Function_(mathematics)http://en.wikipedia.org/wiki/Astronomyhttp://en.wikipedia.org/wiki/Physicshttp://en.wikipedia.org/wiki/Engineeringhttp://en.wikipedia.org/wiki/Computer_graphicshttp://en.wikipedia.org/wiki/Computer-aided_geometric_designhttp://en.wikipedia.org/wiki/Computational_geometryhttp://en.wikipedia.org/wiki/Computational_geometryhttp://en.wikipedia.org/wiki/Mathematicshttp://en.wikipedia.org/wiki/Dimensionhttp://en.wikipedia.org/wiki/Coordinate_systemhttp://en.wikipedia.org/wiki/Coordinate_systemhttp://en.wikipedia.org/wiki/Point_(mathematics)http://en.wikipedia.org/wiki/Plane_(mathematics)http://en.wikipedia.org/wiki/Distancehttp://en.wikipedia.org/wiki/Angle


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A diagram illustrating the relationship between polar and Cartesian

coordinates.

The two polar coordinates r and can be converted to the Cartesiancoordinates x and y by using the trigonometric functions sine and cosine:

while the two Cartesian coordinates x and y can be converted to polarcoordinate r by

(as in the Pythagorean theorem), and

Header Files

stdlib.h

stdlib.h is the header of the general purpose standard library ofC programming language whichincludes functions involving memory allocation, process control, conversions and others. It is

compatible with C++ and is known as cstdlib in C++. The name "stdlib" stands for "standard

library".

graphics.h

http://en.wikipedia.org/wiki/Cartesian_coordinate_systemhttp://en.wikipedia.org/wiki/Cartesian_coordinate_systemhttp://en.wikipedia.org/wiki/Trigonometric_functionhttp://en.wikipedia.org/wiki/Pythagorean_theoremhttp://en.wikipedia.org/wiki/C_programming_languagehttp://en.wikipedia.org/wiki/C%2B%2Bhttp://en.wikipedia.org/wiki/File:Polar_to_cartesian.svghttp://en.wikipedia.org/wiki/Cartesian_coordinate_systemhttp://en.wikipedia.org/wiki/Cartesian_coordinate_systemhttp://en.wikipedia.org/wiki/Trigonometric_functionhttp://en.wikipedia.org/wiki/Pythagorean_theoremhttp://en.wikipedia.org/wiki/C_programming_languagehttp://en.wikipedia.org/wiki/C%2B%2B


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graphics.h is the header of the graphics library ofC programming language.

FunctionsBelow are the important functions and their description mostly used in

graphics applications in C Language.

InitgraphThis function is used to load the graphics drivers and initialize the graphicssystem. For every function, that uses graphics mode. Graphics mode mustbe initialized before using that function.

Deceleration : void far initgraph(int far *driver, int far *mode, char far *path)

Where: Path determines that path to the specified graphics driver.(generally C:\\tc\\bgi)

Remarks:To start the graphics system, you must first call initgraph.

initgraph initializes the graphics system by loading a graphics driver from disk then

putting the system into graphics mode.

initgraph also resets all graphics settings (color, palette, current position, viewport,

etc.) to their defaults, then resets graphresult to 0.

*graphdriver and *graphmode must be set to valid graphics_drivers and

graphics_mode values or you'll get unpredictable results.

detectgraph

Detectgraph function determines the graphics hardware in the system, if thefunction finds a graphics adapter then it returns the highest graphics modethat the adapter supports.

Deceleration : void far detectgraph(int far *driver, int far *mode)

Cleardevice This function clears the graphics screen contents and returnthe control to the location (0,0).

Deceleration : void far cleardevice(void)closegraphThis function shutdown the graphics mode and returns to the position it wasbefore the initgraph function was called. Closegraph function releases all theresources occupied by the graphics system like memry, fonts, drivers etc

Declaration : void far closegraph(void);

Remarks:

closegraph deallocates all memory allocated by the graphics system.

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It then restores the screen to the mode it was in before you called initgraph.(The graphics system deallocates memory, such as the drivers, fonts, and aninternal buffer, through a call to _graphfreemem.)

Setgraphmodesetgraphmode sets the system to graphics mode, clears the screen

Declaration: void far setgraphmode(int mode);

Remarks:

setgraphmode selects a graphics mode different than the default one set byinitgraph. It clears the screen and resets all graphics settings to theirdefaults.

mode must be a valid mode for the current device driver.Return Value:setgraphmode does not return.

graphresult :

Returns an error code for the last unsuccessful graphics operation.

Declaration: int far graphresult(void);

Remarks:

graphresult returns the error code for the last graphics operation that reported anerror, then resets the error level to grOk.

The variable maintained by graphresult is reset to 0 after graphresult hasbeen called. Therefore, you should store the value of graphresult into atemporary variable and then test it.

Return Value: Returns the current graphics error number, (an integer in therange -15 to 0).

graphdefaultsResets all graphics settings to their defaults

Declaration: void far graphdefaults(void);

Remarks:

graphdefaults resets all graphics settings to their defaults:



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sets the viewport to the entire screen. moves the current position to (0,0).sets the default palette colors, background color, and drawing color.sets thedefault fill style and pattern. sets the default text font and justification.

Return Value: None

grapherrormsg:

Returns a pointer to an error message string

Declaration: char *far grapherrormsg(int errorcode);

Remarks:

grapherrormsg returns a pointer to the error message string associated with

errorcode, the value returned by graphresult.

Return Value : Returns a pointer to an error message string.

restorecrtmode

Restores screen mode to pre-initgraph setting

Declaration: void far restorecrtmode(void);

Remarks:

restorecrtmode restores the original video mode detected by initgraph.

This function can be used in conjunction with setgraphmode to switch backand forth between text and graphics modes.

getmaxx, getmaxy

Returns maximum x or y screen coordinate

Declaration:

int far getmaxx(void);

int far getmaxy(void);

Remarks:

getmaxx returns the maximum x value (screen-relative) for the current

graphics driver and mode.getmaxy returns the maximum y value (screen-relative) for the current

graphics driver and mode.

For ex: On a CGA in 320 x 200 mode, getmaxx returns 319 and getmaxy

returns 199.

Return Value:

getmaxx: maximum x screen coordinate

getmaxy: maximum y screen coordinate



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getpixel, putpixel

getpixel gets the color of a specified pixel

putpixel plots a pixel at a specified point

Declaration:unsigned far getpixel(int x, int y);

void far putpixel(int x, int y, int color);

Remarks:

getpixel gets the color of the pixel located at (x,y).

putpixel plots a point in the color defined by color at (x,y).

Return Value:

getpixel returns the color of the given pixel.

putpixel does not return.

getx, gety

getx returns the current position's x coordinate

gety returns the current position's y coordinate

Declaration:

int far getx(void);

int far gety(void);

Remarks:

getx returns the x-coordinate of the current graphics position.

gety returns the y-coordinate of the current graphics position.

Return Value:

getx: x-coordinate of current position , gety: y-coordinate of current position

outtext, outtextxy

outtext displays a string in the viewport (graphics mode)

outtextxy displays a string at the specified location (graphics mode)

Declaration:

void far outtext(char far *textstring);

void far outtextxy(int x, int y, char far *textstring);

Remarks:

outtext and outtextxy display a text string, using the current justification

settings and the current font, direction, and size.



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outtext outputs textstring at the current position (CP)

outtextxy displays textstring in the viewport at the position (x, y)

To maintain code compatibility when using several fonts, use textwidth and

textheight to determine the dimensions of the string.

If a string is printed with the default font using outtext or outtextxy, any

part of the string that extends outside the current viewport is truncated.

With outtext, if the horizontal text justification is LEFT_TEXT and the text

direction is HORIZ_DIR, the CP's x-coordinate is advanced by

textwidth(textstring).

Otherwise, the CP remains unchanged.

outtext and outtextxy are for use in graphics mode; they will not work in

text mode.

Return Value: None

settextjustify

Sets text justification for graphics mode

Declaration: void far settextjustify(int horiz, int vert);

Remarks:

Text output after a call to settextjustify is justified around the current

position (CP) horizontally and vertically, as specified.

The default justification settings are

LEFT_TEXT (for horizontal) and

TOP_TEXT (for vertical)

The enumeration text_just in GRAPHICS.H provides names for the horiz and

vert settings passed to settextjustify.

settextjustify affects text written with outtext and can't be used with

text-mode and stream functions.

Return Value:

If invalid input is passed to settextjustify, graphresult returns -11, and

the current text justification remains unchanged.

settextstyle

Sets the current text characteristics



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Declaration:

void far settextstyle(int font, int direction, int charsize);

Remarks:

settextstyle sets the text font, the direction in which text is displayed,

and the size of the characters.A call to settextstyle affects all text output by outtext and outtextxy.

font

One 8x8 bit-mapped font and several "stroked" fonts are available. The 8x8

bit-mapped font, the default, is built into the graphics system.

The enumeration font_names, defined in GRAPHICS.H, provides names for

the

different font settings.

direction

Font directions supported are horizontal text (left to right) and verticaltext (rotated 90 degrees counterclockwise).

textheight, textwidth

textheight returns the height of a string in pixels

textwidth returns the width of a string in pixels

Declaration:

int far textheight(char far *textstring);

int far textwidth(char far *textstring);

Remarks:

textheight takes the current font size and multiplication factor, and

determines the height of textstring in pixels.

textwidth takes the string length, current font size, and multiplication factor,

and determines the width of textstring in pixels.

These functions are useful for adjusting the spacing between lines,

computing viewport heights, sizing a title to make it fit on a graph or in a

box, etc..

For example, with the 8x8 bit-mapped font and a multiplication factor of 2

(set by settextstyle), the string "Turbo C++" is 16 pixels high.

Instead of doing the computations manually, use textheight to compute the

height of strings, and use textwidth to compute their width.

When you use these functions, no source code modifications are required

when

you select different fonts.



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Return Value:

textheight returns the text height in pixels. textwidth returns the text width

in pixels.

getcolor, setcolorgetcolor returns the current drawing color

setcolor sets the current drawing color

Declaration:

int far getcolor(void);

void far setcolor(int color);

Remarks:

getcolor returns the current drawing color.

setcolor sets the current drawing color to color, which can range from 0 to

getmaxcolor.

To select a drawing color with setcolor, you can pass either the color

number or the equivalent color name.

The drawing color is the value that pixels are set to when the program draws

lines, etc.

For example, in CGAC0 mode (palette number 0), the palette contains four

colors (background, light green, light red, and yellow):

If getcolor returns 1, the current drawing color is light green.

Either setcolor(3) or setcolor(CGA_YELLOW) selects yellow as the drawing

color.

In CGAC3 mode, if getcolor returns 1, the current drawing color is cyan.

Return Value:getcolor returns the current drawing color.

setcolor does not return

getmaxcolor

Returns maximum color value

Declaration: int far getmaxcolor(void);



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Remarks:

getmaxcolor returns the highest valid color value that can be passed to

setcolor for the current graphics driver and mode.

For example, on a 256K EGA, getmaxcolor always returns 15. This means

that any call to setcolor with a value from 0 to 15 is valid.

On a CGA in high-resolution mode getmaxcolor returns 1.

Return Value: Returns the highest available color value.

getbkcolor, setbkcolor

getbkcolor returns the current background color

setbkcolor sets the current background color using the palette

Declaration:

int far getbkcolor(void);

void far setbkcolor(int color);

Remarks:

getbkcolor returns the current background color.

setbkcolor sets the background to the color specified by color.

color is either a number or symbolic name specifying the color to set.

For example, if you want to set the background color to blue, you can callsetbkcolor(BLUE) /* or */ setbkcolor(1)

On CGA and EGA systems, setbkcolor changes the background color by

changing

the first entry in the palette.

On an EGA or a VGA, if you call setpalette or setallpalette to change the

palette colors, the defined symbolic constants might not give the correct

color.

This is because the color parameter to setbkcolor indicates the entry number

in the current palette, rather than a specific color. (Except 0, whichalways sets the background color to black).

Return Value:

getbkcolor returns the current background color.

setbkcolor does not return.

setfillpattern

setfillpattern selects a user-defined fill pattern



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Declaration: void far setfillpattern(char far *upattern, int color);

Remarks:

setfillpattern sets the current fill pattern to a user-defined 8x8 pattern.

Whenever a bit in a pattern's byte is set to 1, the corresponding pixel isplotted.

Return Value: None

Setfillstyle :

Sets the fill pattern and color

Declaration: void far setfillstyle(int pattern, int color);

Remarks:

setfillstyle sets the current fill pattern and fill color.

To set a user-defined fill pattern, do not give a pattern of 12 (USER_FILL) to

setfillstyle; instead, call setfillpattern.

The enumeration fill_patterns, defined in GRAPHICS.H, gives names for the

predefined fill patterns, plus an indicator for a user-defined pattern.

Return Value: None

If invalid input is passed to setfillstyle, graphresult returns -11 (grError), and

the current fill pattern and fill color remain unchanged.

floodfill

Flood-fills a bounded region

Declaration: void far floodfill(int x, int y, int border);

Remarks:

floodfill fills an enclosed area on bitmap devices.

The area bounded by the color border is flooded with the current fill pattern

and fill color.

(x,y) is a "seed point".

If the seed is within an enclosed area, the inside will be filled.

If the seed is outside the enclosed area, the exterior will be filled.



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Return Value:

If an error occurs while flooding a region, graphresult returns -7.

setlinestyle

Sets the current line style and width or pattern

Declaration: void far setlinestyle(int linestyle, unsigned upattern, int

thickness);

Remarks:

setlinestyle sets the style for all lines drawn by line, lineto, rectangle,

drawpoly, etc.

Return Value:

If invalid input is passed to setlinestyle, graphresult returns -11, and thecurrent line style remains unchanged.

imagesize

Returns the number of bytes required to store a bit image

Declaration:

unsigned far imagesize(int left, int top, int right, int bottom);

Remarks:

imagesize determines the size of the memory area required to store a bitimage.

Return Value:

On success, returns the size of the required memory area in bytes.

On error (if the size required for the selected image is >= (64K - 1) bytes),

returns 0xFFFF (-1)

getimage, putimage

getimage saves a bit image of the specified region into memoryputimage outputs a bit image onto the screen

Declaration:

void far getimage(int left, int top, int right, int bottom,void far *bitmap);

void far putimage(int left, int top, void far *bitmap, int op);

Remarks:

getimage copies an image from the screen to memory.



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putimage puts the bit image previously saved with getimage back onto the

screen, with the upper left corner of the image placed at (left,top)

Argument What It Is/Doesbitmap -Points to the area in memory where the bit image is

stored.

-The first two words of this area are used for the widthand

height of the rectangle.

-The remainder holds the image itself.

Bottom left right

top

-(left, top) and (right, bottom) define the rectangular

screen area from which getimage copies the bit image.

-(left, top) is where putimage places the upper left

corner of the stored image.

op Specifies a combination operator that controls how the

color for each destination pixel onscreen is computed,

based on the pixel already onscreen and the

corresponding source pixel in memory.

Return Value: None

setviewport

Sets the current viewport for graphics outputDeclaration:

void far setviewport(int left, int top, int right, int bottom, int clip);

Remarks:

setviewport establishes a new viewport for graphics output.

The viewport's corners are given in absolute screen coordinates by (left,top)

and (right,bottom).

The current position (CP) is moved to (0,0) in the new window.

The clip argument determines whether drawings are clipped (truncated) atthe current viewport boundaries. If clip is non-zero, all drawings will be

clipped to the current viewport.

Return Value:

setviewport does not return.

If invalid input is passed to setviewport, graphresult returns -11, and the

current view settings remain unchanged.



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clearviewport

Clears the current viewport

Declaration: void far clearviewport(void);

Remarks:

clearviewport erases the viewport and moves the CP (current position) tohome (0,0), relative to the viewport.

Return Value: None

line, linerel, lineto

line draws a line between two specified points

linerel draws a line a relative distance from the current position (CP)

lineto draws a line from the current position (CP) to (x,y)

Declaration:void far line(int x1, int y1, int x2, int y2);

void far linerel(int dx, int dy);

void far lineto(int x, int y);

Remarks:

line draws a line from (x1, y1) to (x2, y2) using the current color, line style,

and thickness. It does not update the current position (CP).

linerel draws a line from the CP to a point that is a relative distance (dx, dy)

from the CP, then advances the CP by (dx, dy).

lineto draws a line from the CP to (x, y), then moves the CP to (x, y).

Return Value: None

moverel, moveto

moverel moves the current position (CP) a relative distance moveto moves

the CP to (x, y)

Declaration:

void far moverel(int dx, int dy);

void far moveto(int x, int y);

Remarks:

moverel moves the current position (CP) dx pixels in the x direction and dy

pixels in the y direction.

moveto moves the current position (CP) to viewport position (x, y).



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Return Value: None

bar: Draws a bar

Declaration: void far bar(int left, int top, int right, int bottom);

Remarks:

bar draws a filled-in, rectangular, two-dimensional bar.

The bar is filled using the current fill pattern and fill color. bar does not

outline the bar.

To draw an outlined two-dimensional bar, use bar3d with depth = 0.

Parameters What they are(left, top) the rectangle's upper left corner(right, bottom) the rectangle's lower right corner

The coordinates are in pixels.

Return Value: None

bar3d: Draws a 3-D bar

Declaration: void far bar3d(int left, int top, int right, int bottom, int depth, int

topflag);

Remarks:

bar3d draws a three-dimensional rectangular bar, then fills it using the current fillpattern and fill color.

The three-dimensional outline of the bar is drawn in the current line style and color.

Parameters What they aredepth Bar's depth in pixels

(left, top) the rectangle's upper left corner(right, bottom) the rectangle's lower right cornertopflag Governs whether a three-dimensional

top is put on the bar

If topflag is non-zero, a top is put on the bar. If topflag is 0, no top is put on the bar:This makes it possible to stack several bars on top of one another.

To calculate a typical depth for bar3d, take 25% of the width of the bar,like this:

bar3d(left, top, right, bottom, (right-left)/4, 1);

Return Value: None

Rectangle : Draws a rectangle (graphics mode)



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Declaration: void far rectangle(int left, int top, int right, int bottom);

Remarks:

rectangle draws a rectangle in the current line style, thickness, and drawing color.

(left,top) is the upper left corner of the rectangle, and (right,bottom) is its lowerright corner.

Return Value: None

arc, circle, pieslice

arc draws a circular arc

circle draws a circle

pieslice draws and fills a circular pie slice

Declaration:void far arc(int x, int y, int stangle, int endangle, int radius);

void far circle(int x, int y, int radius);

void far pieslice(int x, int y, int stangle, int endangle, int radius);

Remarks:

arc draws a circular arc in the current drawing color.

circle draws a circle in the current drawing color.

pieslice draws a pie slice in the current drawing color, then fills it using

the current fill pattern and fill color.

Argument What It Is/Does(x,y) Center point of arc, circle, or pie slice

stangle Start angle in degrees

endangle End angle in degreesradius Radius of arc, circle, and pieslice

The arc or slice travels from stangle to endangle.

If stangle = 0 and endangle = 360, the call to arc draws a complete circle.

Angle for arc, circle, and pieslice (counter-clockwise)

90 degrees

|

|

180 --------------------0 degrees,

degrees | 360 degrees

|

270 degrees



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ReturnValue: None

Ellipse, fillellipse, sector

ellipse draws an elliptical arcfillellipse draws and fills an ellipse

sector draws and fills an elliptical pie slice

Declaration:

void far ellipse(int x, int y, int stangle, int endangle, int xradius, int yradius);

void far fillellipse(int x, int y, int xradius, int yradius);

void far sector(int x, int y, int stangle, int endangle, int xradius, int yradius);

Remarks:

ellipse draws an elliptical arc in the current drawing color.

fillellipse draws an ellipse, then fills the ellipse with the current fill color and fill

pattern.

sector draws and fills an elliptical pie slice in the current drawing color, then fills it

using the pattern and color defined by setfillstyle or setfillpattern.

Argument What It Is(x,y) Center of ellipseXradius Horizontal axis

Yradius Vertical axisStangle Starting angleEndangle Ending angle

The ellipse or sector travels from stangle to endangle.

If stangle = 0 and endangle = 360, the call to ellipse draws a complete ellipse.

ReturnValue: None

drawpoly, fillpoly

drawpoly draws the outline of a polygon

fillpoly draws and fills a polygon

Declaration:

void far drawpoly(int numpoints, int far *polypoints);

void far fillpoly(int numpoints, int far *polypoints);

Remarks:



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C Graphics

drawpoly draws a polygon using the current line style and color.

fillpoly draws the outline of a polygon using the current line style and color, then

fills the polygon using the current fill pattern and fill color.

Argument What It Isnumpoints Specifies number of pointspolypoints Points to a sequence of (numpoints x 2)

integers

Each pair of integers gives the x and y coordinates of a point on the polygon.

To draw a closed figure with N vertices, you must pass N+1 coordinates to

drawpoly, where the Nth coordinate == the 0th coordinate.

ReturnValue: None

C graphics basic

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