Module rastergraphics - Graphics primitives for rasters

Graphics primitives for rasters.

Maintainer:

David Wood <D.C.Wood@kent.ac.uk>

Index

Declarations

spectrum.occ:31Function map.to.components.spectrum

BYTE, BYTE, BYTE FUNCTION map.to.components.spectrum (VAL REAL64 x)

Maps code value into three BYTEs representing primary colours (not necessarily RGB), with smooth transitions.

Parameters:

VAL REAL64 x Value (0.0 <= x < 1.0)

Returns:

BYTE "red", "green", "blue"

spectrum.occ:41Function smooth

BYTE INLINE FUNCTION smooth (VAL REAL64 x)

Smooth transition.

Parameters:

VAL REAL64 x Argument; 0.0 <= x <= 1.0

Returns:

BYTE 0 <= "colour" <= #FF

spectrum.occ:75Function map.to.components.wheel

BYTE, BYTE, BYTE FUNCTION map.to.components.wheel (VAL REAL64 x)

As map.to.components.spectrum, but without mapping through black.

spectrum.occ:115Function pack.colour.permuted

INT FUNCTION pack.colour.permuted (VAL BYTE r, g, b, VAL INT permute)

Maps three BYTEs representing colours to an INT, according to the code permute.

Parameters:

VAL BYTE r, g, b "red", "green", "blue"
VAL INT permute Permutation code

Returns:

INT #rrggbb

spectrum.occ:159Function map.colour.spectrum

INT FUNCTION map.colour.spectrum (VAL REAL64 x, VAL INT permute)

Maps x (0.0 <= x < 1.0) to INT representing a colour, according to the code permute. Shades from black through "red", "yellow", "green", "cyan", "magenta", back to "red", and finally black.

x >= 1.0 shown as black; x < 0.0 shown as dark grey.

Parameters:

VAL REAL64 x (0.0 <= x < 1.0)
VAL INT permute Permutation code

Returns:

INT #rrggbb

spectrum.occ:188Function map.colour.wheel

INT FUNCTION map.colour.wheel (VAL REAL64 x, VAL INT permute)

Maps x (0.0 <= x < 1.0) to INT representing a colour, according to the code permute. Shades from "red" through "yellow", "green", "cyan", "magenta", back to "red".

x >= 1.0 shown as black; x < 0.0 shown as white.

Parameters:

VAL REAL64 x (0.0 <= x < 1.0)
VAL INT permute Permutation code

Returns:

INT #rrggbb

circle.occ:34Process draw.circle

PROC draw.circle (VAL INT x.0, y.0, radius, VAL INT colour, [][]INT raster)

Draws a circle.

Clips as necessary.

Based on Foley & van Dam, Computer Graphics Principles and Practice, Second Edition in C, Fig. 3.16.

Parameters:

VAL INT x.0, y.0 Centre
VAL INT radius Radius
VAL INT colour Colour
[][]INT raster Raster

circle.occ:42Process points.1

INLINE PROC points.1 (VAL INT x, y)

Plots eight points at (+/-x, +/-y) relative to centre (x.0, y0), all within raster (fast).

circle.occ:59Process points.2

PROC points.2 (VAL INT x, y)

Plots eight points at (+/-x, +/-y) relative to centre (x.0, y0), some outside raster (slow).

circle.occ:65Process point

PROC point (VAL INT x, y)

Plot point if inside raster

Parameters:

VAL INT x, y Coordinates

circle.occ:93Process points

INLINE PROC points (VAL INT x, y, VAL BOOL b)

Decide how to plot points

Parameters:

VAL INT x, y Coordinates
VAL BOOL b How to plot

disc2.occ:30Process fill.circle.diameter

PROC fill.circle.diameter (VAL INT x, y, d, VAL INT colour, [][]INT raster)

Draws a solid circle. Clips as necessary.

Parameters:

VAL INT x, y Coordinates of centre
VAL INT d Diameter
VAL INT colour Colour
[][]INT raster Raster

lines.occ:31Process draw.horizontal.line

PROC draw.horizontal.line (VAL INT x, y, l, VAL INT colour, [][]INT raster)

Draws a horizontal line.

Clips as necessary.

Parameters:

VAL INT x, y Starting point
VAL INT l Length
VAL INT colour Colour
[][]INT raster Raster

lines.occ:67Process draw.vertical.line

PROC draw.vertical.line (VAL INT x, y, l, VAL INT colour, [][]INT raster)

Draws a vertical line.

Clips as necessary.

Parameters:

VAL INT x, y Starting point
VAL INT l Length
VAL INT colour Colour
[][]INT raster Raster

lines.occ:104Process draw.rectangle

PROC draw.rectangle (VAL INT x, y, w, h, VAL INT colour, [][]INT raster)

Draws a rectangular box.

Clips as necessary.

Parameters:

VAL INT x, y Top left corner
VAL INT w Width
VAL INT h Height/depth
VAL INT colour Colour
[][]INT raster Raster

graphics.inc:27Group COLOUR

Common colours

Assume coded as #rrggbb, which ain't necessarily so.

graphics.inc:31Constant COLOUR.BLACK

VAL INT COLOUR.BLACK

graphics.inc:32Constant COLOUR.WHITE

VAL INT COLOUR.WHITE

graphics.inc:33Constant COLOUR.RED

VAL INT COLOUR.RED

graphics.inc:34Constant COLOUR.GREEN

VAL INT COLOUR.GREEN

graphics.inc:35Constant COLOUR.BLUE

VAL INT COLOUR.BLUE

graphics.inc:36Constant COLOUR.YELLOW

VAL INT COLOUR.YELLOW

graphics.inc:37Constant COLOUR.CYAN

VAL INT COLOUR.CYAN

graphics.inc:38Constant COLOUR.MAGENTA

VAL INT COLOUR.MAGENTA

graphics.inc:39Constant COLOUR.GREY

VAL INT COLOUR.GREY

graphics.inc:40Constant COLOUR.ORANGE

VAL INT COLOUR.ORANGE

graphics.inc:41Constant COLOUR.PINK

VAL INT COLOUR.PINK

graphics.inc:42Constant COLOUR.SKY

VAL INT COLOUR.SKY

graphics.inc:43Constant COLOUR.MAROON

VAL INT COLOUR.MAROON

graphics.inc:44Constant COLOUR.BROWN

VAL INT COLOUR.BROWN

graphics.inc:45Constant COLOUR.NAVY

VAL INT COLOUR.NAVY

graphics.inc:46Constant COLOUR.PURPLE

VAL INT COLOUR.PURPLE

graphics.inc:47Constant COLOUR.VIOLET

VAL INT COLOUR.VIOLET

graphics.inc:49Constant COLOUR.OCTARINE

VAL INT COLOUR.OCTARINE

graphics.inc:61Function pack.colour

INT INLINE FUNCTION pack.colour (VAL BYTE r, g, b)

Pack RGB BYTEs to an INT.

Assume coded as #rrggbb, which ain't necessarily so.

Parameters:

VAL BYTE r, g, b Primary colour components

Returns:

INT #rrggbb

graphics.inc:69Function pack.colour.float

INT INLINE FUNCTION pack.colour.float (VAL REAL32 r, g, b)

As pack.colour, but taking REAL32 arguments.

Parameters:

VAL REAL32 r, g, b Primary colour components in the range 0.0 to 1.0

Returns:

INT #rrggbb

graphics.inc:78Function unpack.colour

BYTE, BYTE, BYTE INLINE FUNCTION unpack.colour (VAL INT c)

Unpack an INT to RGB BYTEs.

Parameters:

VAL INT c #rrggbb

Returns:

BYTE r, g, b Primary colour components

graphics.inc:82Group PALETTE

Codes for permute arguments.

graphics.inc:86Constant PALETTE.RGB

VAL INT PALETTE.RGB

graphics.inc:87Constant PALETTE.BGR

VAL INT PALETTE.BGR

graphics.inc:88Constant PALETTE.RBG

VAL INT PALETTE.RBG

graphics.inc:89Constant PALETTE.BRG

VAL INT PALETTE.BRG

graphics.inc:90Constant PALETTE.GRB

VAL INT PALETTE.GRB

graphics.inc:91Constant PALETTE.GBR

VAL INT PALETTE.GBR

disc.occ:30Process fill.circle

PROC fill.circle (VAL INT x, y, r, VAL INT colour, [][]INT raster)

Draws a solid circle. Clips as necessary.

Parameters:

VAL INT x, y Coordinates of centre
VAL INT r Radius
VAL INT colour Colour
[][]INT raster Raster

arc.occ:33Process draw.arc

PROC draw.arc (VAL INT x.0, y.0, radius, VAL ANGLE t.0, t.1, VAL INT colour, [][]INT raster)

Draws a circular arc.

Parameters:

VAL INT x.0, y.0 Coordinates of centre
VAL INT radius Radius
VAL ANGLE t.0, t.1 Range of ANGLEs
VAL INT colour Colour
[][]INT raster Raster

arc.occ:39Process arc

PROC arc (VAL ANGLE t.0, t.1)

Basic PROC; arc <= ANGLE.RIGHT

Parameters:

VAL ANGLE t.0, t.1 Range of ANGLEs

line.occ:37Process draw.line

PROC draw.line (INT x.0, y.0, VAL INT d.x, d.y, VAL INT c.0, c.1, [][]INT raster)

Draw a straight line.

Returns end point in (x.0, y.0).

Does nothing if (x.0, y.0) is outside raster.

Based on Foley & van Dam, Computer Graphics Principles and Practice, Second Edition in C, Fig. 3.8.

Parameters:

INT x.0, y.0 Starting point
VAL INT d.x, d.y Relative position of end point
VAL INT c.0 Stop when line hits this colour
VAL INT c.1 Draw in this colour ...
[][]INT raster ... on this raster

colourspace.occ:34Function desaturate.colour

INT FUNCTION desaturate.colour (VAL INT colour, amount)

Desaturate a colour value.

This adds amount to each of the colour's components, capping them at #FF.

Parameters:

VAL INT colour Colour
VAL INT amount Amount to add

Returns:

INT The new colour

colourspace.occ:69Function hsv.to.rgb

INT FUNCTION hsv.to.rgb (VAL REAL32 h, s, v)

Convert a colour from HSV to RGB.

The HSV colourspace specifies colour shades in terms of hue (basic colour), saturation and value (brightness), each a real value between 0 and 1. It's useful if you want to turn a continuous range of values into a smooth series of colours: fix the saturation and value and vary the hue.

This is an implementation of http://www.cs.rit.edu/~ncs/color/t_convert.html N. Schaller's algorithm.

Parameters:

VAL REAL32 h Hue
VAL REAL32 s Saturation
VAL REAL32 v Value

Returns:

INT #rrggbb

rectangle.occ:32Process fill.rectangle

PROC fill.rectangle (VAL INT x.0, y.0, w.0, h.0, VAL INT colour, [][]INT raster)

Draws a solid rectangle.

Clips as necessary.

Parameters:

VAL INT x.0, y.0 Top left corner
VAL INT w.0 Width
VAL INT h.0 Height/depth
VAL INT colour Colour
[][]INT raster Raster

rectangle.occ:78Process fill.square

PROC fill.square (VAL INT x, y, s, VAL INT colour, [][]INT raster)

Draw a solid square.

dither.occ:28Function dither

INT FUNCTION dither (VAL INT n, i, j)

Dither

Parameters:

VAL INT n Order
VAL INT i, j Coordinates

Returns:

INT Dither

dither.occ:51Function undither

INT, INT FUNCTION undither (VAL INT n, k)

Reverse Dither

Parameters:

VAL INT n Order
VAL INT k Count

Returns:

INT i, j Coordinates

copy.occ:41Process copy.raster

PROC copy.raster (VAL [][]INT src, VAL INT x, y, c, f, [][]INT dst)

Copy one raster onto another.

One corner of src always maps to (x, y) of dst.

Let the least significant three bits of f be abc:

  • a = 1: flip about \, then
  • b = 1: flip about |
  • c = 1: flip about -

Hence

  • f = 7: flip about /

Parameters:

VAL [][]INT src Source raster
VAL INT x, y Top left of target in dst
VAL INT c Transparent colour -- don't copy
VAL INT f Orientation
[][]INT dst Destination raster

copy.occ:143Process overwrite.raster

PROC overwrite.raster (VAL [][]INT src, VAL INT x, y, f, [][]INT dst)

cordic.occ:55Function CORDIC

INT, INT FUNCTION CORDIC (VAL INT X, Y, VAL ANGLE theta)

CORDIC rotation algorithm.

See here for details.

Rotates vector through angle

Parameters:

VAL INT X, Y Coordinates of vector
VAL ANGLE theta Angle

Returns:

INT X, Y Rotated through theta

cordic.occ:65Constant CORDIC.CONST

VAL INT CORDIC.CONST

Magic constant

cordic.occ:101Function CIDROC

INT, ANGLE FUNCTION CIDROC (VAL INT X, Y)

Inverse CORDIC algorithm; Converts Cartesian (X, Y) to polar coordinates.

Parameters:

VAL INT X, Y Coordinate of vector

Returns:

INT radius sqrt(X^2 + Y^2)
ANGLE angle arctan(Y/X)

cordic.occ:105Constant CORDIC.CONST

VAL INT CORDIC.CONST

Magic constant

wallpaper.occ:27Process draw.wallpaper

PROC draw.wallpaper (VAL [][]INT src, [][]INT dst)

Cover dst with copies of dst

Parameters:

VAL [][]INT src Source raster
[][]INT dst Destination raster

angle.inc:28Data type ANGLE

DATA TYPE ANGLE

ANGLE data type

An ANGLE is measured in units of 2^32 bits = 1 turn = 4 right angles = 2 pi radians = 360 degrees = 400 grades. Like times, angles wrap round without overflowing.

angle.inc:30Group ANGLE

constants

angle.inc:32Constant ANGLE.STRAIGHT

VAL ANGLE ANGLE.STRAIGHT

2^31 (exact)

angle.inc:33Constant ANGLE.RIGHT

VAL ANGLE ANGLE.RIGHT

2^30 (exact)

angle.inc:34Constant ANGLE.RADIAN

VAL ANGLE ANGLE.RADIAN

2^31 / pi (approx.)

angle.inc:35Constant ANGLE.DEGREE

VAL ANGLE ANGLE.DEGREE

2^32 / 360 (approx.)

angle.inc:38Constant ANGLE.GRADE

VAL ANGLE ANGLE.GRADE

2^32 / 400 (approx.)

angle.inc:48Operator + (ANGLE, ANGLE)

ANGLE INLINE FUNCTION "+" (VAL ANGLE X, Y)

Addition operator

Parameters:

VAL ANGLE X, Y Operands

Returns:

ANGLE X + Y

angle.inc:49Operator - (ANGLE, ANGLE)

ANGLE INLINE FUNCTION "-" (VAL ANGLE X, Y)

angle.inc:50Operator * (ANGLE, INT)

ANGLE INLINE FUNCTION "**" (VAL ANGLE X, VAL INT Y)

angle.inc:51Operator * (INT, ANGLE)

ANGLE INLINE FUNCTION "**" (VAL INT X, VAL ANGLE Y)

angle.inc:52Operator / (ANGLE, INT)

ANGLE INLINE FUNCTION "/" (VAL ANGLE X, VAL INT Y)

angle.inc:53Operator - (ANGLE)

ANGLE INLINE FUNCTION "-" (VAL ANGLE X)

angle.inc:54Operator > (ANGLE, ANGLE)

BOOL INLINE FUNCTION ">" (VAL ANGLE X, Y)

angle.inc:55Operator < (ANGLE, ANGLE)

BOOL INLINE FUNCTION "<" (VAL ANGLE X, Y)

angle.inc:56Operator <= (ANGLE, ANGLE)

BOOL INLINE FUNCTION "<=" (VAL ANGLE X, Y)

angle.inc:57Operator >= (ANGLE, ANGLE)

BOOL INLINE FUNCTION ">=" (VAL ANGLE X, Y)

angle.inc:64Operator ~ (ANGLE)

ANGLE INLINE FUNCTION "~" (VAL ANGLE X)

Reverse operator

Parameters:

VAL ANGLE X Operands

Returns:

ANGLE Opposite direction

hit.occ:29Function circle.hits

BOOL FUNCTION circle.hits (VAL INT X, Y, radius, colour, VAL [][]INT raster)

Does circle hit anything?

Parameters:

VAL INT X, Y Centre of circle
VAL INT radius Radius
VAL INT colour Colour of target
VAL [][]INT raster Raster

ellipse.occ:31Process fill.ellipse.radii

PROC fill.ellipse.radii (VAL INT x, y, a, b, VAL INT colour, [][]INT raster)

Draws a solid ellipse. Clips as necessary.

Parameters:

VAL INT x, y Coordinates of centre
VAL INT a, b X and Y radii
VAL INT colour Colour
[][]INT raster Raster