Drawing Procedures

Notes:

1. include setscreen ("graphics") as the first executable line of code
2. the origin of the coordinate grid (0, 0) is at the bottom left of the run window
3. the axes run from the origin to maxx and maxy
4. procedures without fill in their names produce a figure outlined in the specified colour
5. procedures with fill in their names produce a figure filled with the specified colour

Basics

drawdot (x, y, colour)

• (x, y) are the coordinates of the dot
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

drawline (x1, y1, x2, y2, colour)

• the line runs from (x1, y1) to (x2, y2)
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

Boxes & rectangular figures

drawbox (bottom-x, bottom-y, top-x, top-y, colour)
drawfillbox (bottom-x, bottom-y, top-x, top-y, colour)

• (bottom-x, bottom-y) is the bottom left corner
• (top-x, top-y) is the top right corner
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

drawmapleleaf (bottom-x, bottom-y, top-x, top-y, colour)
drawfillmapleleaf (bottom-x, bottom-y, top-x, top-y, colour)

• (bottom-x, bottom-y) is the bottom left corner
• (top-x, top-y) is the top right corner
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

drawstar (bottom-x, bottom-y, top-x, top-y, colour)
drawfillstar (bottom-x, bottom-y, top-x, top-y, colour)

• (bottom-x, bottom-y) is the bottom left corner
• (top-x, top-y) is the top right corner
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

Ovals & arcs

drawoval (x, y, x-radius, y-radius, colour)
drawfilloval (x, y, x-radius, y-radius, colour)

• (x, y) are the coordinates of the centre
• x-radius and y-radius are the lengths in pixels from the centre to the edge
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

drawarc (x, y, x-radius, y-radius, starting-angle, ending-angle, colour)
drawfillarc (x, y, x-radius, y-radius, starting-angle, ending-angle, colour)

• (x, y) are the coordinates of the centre
• x-radius and y-radius are the lengths in pixels from the centre to the edge
• starting-angle and ending-angle are expressed in degrees in relation to the x-axis
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

Advanced

drawfill (x, y, fill-colour, border-colour)

• (x, y) are the coordinates of the centre
• fill-colour is the colour which will spread from the centre until the border-colour is reached
• border-colour is the colour which marks the end of the area to be filled with the fill-colour

drawpolygon (x-array, y-array, number-of-points, colour)

• x-array is an array of x-coordinates
• y-array is an array of y-coordinates
• number-of-points is the number of coordinate pairs to be constructed from the two coordinate arrays
• the points are
  • ( x-array (1), y-array (1) )
  • ( x-array (2), y-array (2) )
  • ( x-array (3), y-array (3) )
  •    …
  • ( x-array (number-of-points), y-array (number-of-points) )
• colour is any valid predefined colour name (blue, yellow, etc.) or integer colour code

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