Graphics Extension

This is Graphics Extension Command Reference v1.6

Graphics Extension (Hand BASIC v1.4 or later) is available via In-App Purchase. 

To open purchase screen:

 - Type PURCHASE

 - Or, type ACTION then select Purchase

 - Or, run a program that uses Graphics

NOTE: To toggle title bar (hide/show) in Screen1 make double touch (two fingers at same time)

Some sample programs (included in App):

(for more programs see CBM Hand BASIC Blog)

SCREEN – Set Screen Mode

    SCREEN I

        I = Screen Index

             0    for text screen (default)

             1    for graphic screen. 

                   Portrait Dimension 

                       320 x 460 pixels for iPhone/iPod Touch. 

                       768 x 1004 pixels for iPad

                   Landscape Dimension

                       480 x 300 pixels for iPhone/iPod Touch. 

                       1024 x 748 pixels for iPad

             2    graphics screen for retina display (useful only for retina display devices)

                   Portrait Dimension 

                       640 x 920 pixels for iPhone/iPod Touch. 

                       1536 x 2008 pixels for iPad

                   Landscape Dimension

                       960 x 600 pixels for iPhone/iPod Touch. 

                       2048 x 1496 pixels for iPad                    

             Coordinate system: x axis goes from left to right, y axis goes from top to bottom

            HINT:  you usually design the screen to be either Portrait or Landscape but not both

    Example:

    10 SCREEN 1 : CLS

    20 CIRCLE 160, 200, 100, 1, 1

    30 GOTO 30

CLS – Clear Screen

    Clears current selected Screen. Current Screen is set by SCREEN command

    Example:

    10 SCREEN 1 : CLS

    20 CIRCLE 160, 200, 100, 1, 1

    30 GOTO 30

TITLE – Set graphics screen title

    TITLE N

        N = string value for screen title

    Example:

    10 SCREEN 1 : CLS

    20 TITLE "My Title!"

    30 CIRCLE 160, 200, 100, 1, 1

    40 GOTO 40

SLEEP – Wait for the specified time. Puts CPU into sleep

    Waits the specified time before continuing the program. Saves CPU cycles which in turn saves the battery

    SLEEP T

        T = Sleep time in milliseconds (1 second = 1000 millisecond).

    Example:

    10 SCREEN 1 : CLS

    20 CIRCLE 160, 200, 100, 1, 1

    30 SLEEP 5000

ANTIALIAS – Enable/Disable antialiasing

    ANTIALIAS f

        f = 0 / 1 (default is enabled f = 1)

    Example:

    10 SCREEN 1 : CLS

    20 ANTIALIAS 0

    30 LINE 160, 200, 260, 300, 2

    40 GOTO 40

PSET – Draw Pixel (Pixel Set)

    PSET X, Y, C

        X = x-value of the coordinate for pixel 

        Y = y-value of the coordinate for pixel

        C = Color 0 – 15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS

    20 PSET 160, 200, 1

    30 GOTO 30

LINE – Draw Line

    LINE X1, Y1, X2, Y2, C

        X1, Y1 = line start coordinate

        X2, Y2 = line end coordinate

        C = line color 0 – 15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS

    20 LINE 160, 200, 260, 300, 2

    30 GOTO 30

MOVETO – Move current point to coordinate

    moves current point without drawing

    MOVETO X, Y

        X, Y = new current point coordinate

    Example:

    10 SCREEN 1 : CLS

    20 MOVETO 160, 200

    30 LINETO 260, 300, 1

    40 GOTO 40

LINETO – Draw line from current point to coordinate

    LINETO X, Y, C

        X, Y = line end coordinate

        C = line color 0 – 15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS

    20 MOVETO 160, 200

    30 LINETO 260, 300, 1

    40 GOTO 40

RECT – Draw Filled Rectangle

    RECT X1, Y1, X2, Y2, C

        X1, Y1 = rectangle upper left position

        X2, Y2 = rectangle bottom right position

       C = rectangle color 0 – 15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS

    20 RECT 160, 200, 260, 300, 1

    30 GOTO 30

FRAME – Draw Frame (None filled Rectangle)

    FRAME X1, Y1, X2, Y2, C

        X1, Y1 = frame upper left position

        X2, Y2 = frame bottom right position

       C = frame color 0 – 15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS

    20 FRAME 160, 200, 260, 300, 1

    30 GOTO 30

CIRCLE – Draw Circle

   CIRCLE X, Y, R, C, F

        X, Y = center of circle coordinate

        R = circle radius

        C = circle color 0-15 or index of user defined color

        F = circle is filled flag (0/1) 

    Example:

    10 SCREEN 1 : CLS 

    20 CIRCLE 160, 200, 100, 1, 1

    30 GOTO 30

ARC – Draw Arc

    ARC X, Y, R, S, E, C, F

        X, Y = center of arc coordinate

        R = arc radius

        S = start angle of arc in degrees

        E = end angle of arc in degrees

        C = arc color 0-15 or index of user defined color

        F = arc is filled flag (0/1) 

    Example:

    10 SCREEN 1 : CLS

    20 ARC 160, 200, 100, 0, 45, 1, 1

    30 GOTO 30

ELLIPSE – Draw Ellipse

    Draw Ellipse inside given rectangle coordinates

    ELLIPSE X1, Y1, X2, Y2,  C, F

        X1, Y1, X2, Y2 = rectangle to draw ellipse inside

        C = ellipse color 0-15 or index of user defined color

        F = ellipse is filled flag (0/1) 

    Example:

    10 SCREEN 1 : CLS 

    20 ELLIPSE 160, 200, 300, 300, 3, 1

    30 GOTO 30

GPRINT – Draw Text

    GPRINT T, X, Y, C

        T = string value of the text to draw

        X, Y = lower left position of the text

        C = text color 0-15 or index of user defined color

    Example:

    10 SCREEN 1 : CLS 

    20 GPRINT "Hello World!", 160, 200, 2

    30 GOTO 30

Commodore Colors

CSET - Define new color 

    CSET I, R, G, B, A

        I = index of color I > 15. this index can be used in drawing commands

        R = red component of color 0-255

        G = green component of color 0-255

        B = blue component of color 0-255

        A = alpha channel (transparency) of color 0-255

    Example:

    10 SCREEN 1 : CLS

    20 CSET 100, 255, 0, 0, 128

    30 CIRCLE 160, 200, 100, 1, 100

    40 GOTO 40

LSET - set Line style

    affects all drawing commands except GPRINT

    LSET W, C

        W = line width in pixels. default is 1

        C = line cap 0 - 2

                0 squared-off end (default)

                1 rounded (extended)

                2 extended squared-off end

    Example:

    10 SCREEN 1 : CLS

    20 LSET 4, 1

    30 LINE 160, 200, 260, 300, 2

    40 GOTO 40

    this sets drawn line style to be 4 pixels wide and line end is rounded and extends beyond givin coordinates

FSET - Set current Font for GPRINT

    FSET T, S

        T = string of full font name

        S = point size of font

        to see the list of available font names use direct command FONTS.

        to filter fonts use FONTS "filter"

        Please note: not all fonts are compatible with Hand BASIC.

    Example:

    10 SCREEN 1 : CLS 

    20 FSET "Courier", 16

    30 GPRINT "Hello World!", 160, 200, 2

    40 GOTO 40

DRAW - Draw using Graphics Macro Language (GML)

    Draw T

        T = string having list of parameters

                Parameters:

                    CI = set color to I = color index

                    draw line from current point (last reached point)   by moving:

                    RV = moving to right V pixels (V is an integer value)

                    LV = moving to left V pixels

                    UV = moving to up V pixels

                    DV = moving to down V pixels

                    EV = moving up and right V pixels

                    FV = moving down and right V pixels

                    GV = moving down and left V pixels

                    HV = moving up and left V pixels

                    MX,Y = move to point (X,Y)

                                  if you add +/- to X or Y the movement is relative to last point

                    Modifiers:

                    B        move but does not draw. affects the next command only

                    N        draws and returns to the starting point

                    you can add spaces if you like to make string readable!

    Example:

    10 SCREEN 1 : CLS 

    20 DRAW "BM100,100C1R20U20L20D20"

    30 GOTO 30

TRIANGLE  - Draw any kind of triangle

    drawing triangles almost  allow to draw anything

    TRIANGLE X1, Y1, X2, Y2, X3, Y3, C, F

        X1, Y1 =  first corner coordinate 

        X2, Y2 = second corner coordinate

        X3, Y3 = third corner coordinate

        C = index of color

        F = fill triangle flag 0/1

POLYGON - Draw any kind of polygon

    POLYGON XC, YC, R, S, T, C, F

        XC, YC =  center of polygon

        R = radius of polygon

        S = number of polygon sides (3-20)

        T = polygon rotation angle in degrees (0-360) usually set to zero

        C = index of polygon color

        F = fill polygon flag 0/1

    Example:

    10 SCREEN 1 : CLS

    20 POLYGON 160,230, 100, 5, 0, 1,0 

    30 SLEEP 200: GOTO 30

    This draws red outlined polygon with five sides

STAR - Draw any kind of star

    STAR XC, YC, OR, IR, V, R, C, F

        XC, YC = center of star

        OR = outer radius of star

        IR = inner radius of star (usually IR < OR)

        V = number of vertexes of star (3-20)

        R = star rotation angle in degrees (0-360) usually set to zero

        C = index of star color

        F = fill star flag 0/1

    Example:

    10 SCREEN 1 : CLS

    20 STAR 160, 230, 120,40, 5, 0, 6,1

    30 GOTO 30

    This draws a yellow filled star with five vertexes

BEGINFRAME - Begin drawing into frame

    Used to make animations.   All drawings are buffered until ENDFRAME

ENDFRAME - End drawing into frame

    Used to make animations.   All  buffered drawings are flushed to screen

    See samples: BOUNCE.BAS, RECTS.BAS, FSTARS.BAS

    HINT:  use TI to control timing (TI returns time: 1 = 1/60 second)

    BeginFrame/EndFrame are also useful for minimizing heavy drawing time (since screen refreshing is prevented until finish)

Reading User Taps:

    This subroutine  shows how to read taps into (X, Y) 

    3000 REM [SUB READ USER TAP]

    3010 DEF FN PK(A)=PEEK(A)+PEEK(A+1)*256

    3020 XT=1030

    3030 YT=1032

    3040 POKE 1024,0

    3050 IF PEEK(1024) = 0 THEN GOTO 3050

    3060 X = FN PK(XT) : Y = FN PK(YT)

    3070 RETURN 

    FN PK(A) reads 16bit integer from memory address A

    Address 1024 has tap event type

    Address 1030 has X coordinate of user tap

    Address 1032 has Y coordinate of user tap

    See QUIZ.BAS sample program