Drawing instructions may operate within the absolute coordinates of the display area, namely x values ranging between 0 and 239 and y values between 0 and 199. Alternatively, they may operate relative to the current drawing position.

CURSET sets the drawing position or cursor to an absolute coordinate. When HIRES is entered, the cursor is automatically set to (0,0). Many high-resolution programs do not require drawing to start at this point, so CURSET is used to position the cursor initially. Subsequently, the instruction is used whenever an absolute cursor setting is needed.

Once the right starting position is achieved the DRAW instruction can be used to plot a figure. DRAW X,Y,FB draws a line from the current cursor position to a position X away on the x-axis and Y away on the y-axis, with a given FB code: thus relative coordinates are used.

Listing 3 employs CURSET and DRAW to plot 'snowflakes' randomly on the screen until the S key is pressed.

DRAW normally draws solid lines but the PATTERN instruction can be used to give a different layout to the lines drawn. PATTERN is followed by a value between 0 and 255 which determines the level of solidity, giving, for example, dotted or dashed lines. The pattern of lines is determined by the binary layout of the integer in the PATTERN instruction. For example, lines with long dashes may be achieved by PATTERN 231 (binary is 11100111) Listing 4 shows the effect of any given pattern value. Sometimes you may want to move the cursor relative to its current placing. This is done by CURMOV. The instruction's format resembles CURSET, coordinates are not absolute. The difference is illustrated in the following example, which also introduces the CIRCLE instruction. This command has a format of CIRCLE R,FB where R is the radius of the circle drawn, its centre being at the current drawing position. Listing 5 fills the screen with circles.

CIRCLE is also affected by the current PATTERN setting, so normally we reset a PATTERN of 255 if dashed lines have previously been used.

Although HIRES is designed for drawing rather than printing, text can be displayed, using the CHAR instruction. This has three parameters. The first defines the character to be plotted as an ASCII value; the second determines whether it is to be in the standard (0) or alternate (1) character set, and the third is the FB code. The character is plotted at the current cursor position, so CURMOV or CURSET should accompany CHAR. For example, to place a text message M$ on the HIRES screen starting at the current position, the following routine could be used:

FOR C=1 TO LEN(M$):CHAR ASC(MID$(M$,C,1)),0,1:CURMOV 6,0,0:NEXT

As well as printing text, CHAR can also plot attributes. However, the FILL instruction is generally better equipped for this task. This command has the form FILL L,B,N: it fills L lines of B bytes with the value N, starting at the current cursor position. Oric 1 owners should be a little wary here since FILL does not necessarily update the cursor position correctly.

Listing 6 places random foreground colour attributes in byte 1 of all lines, and then draws a solid circle to show the colours.

Another keyword that gets down to the byte level is POINT. POINT (X,Y) examines the pixel (X,Y) and returns a value 0 if it is in background colour or -1 if it is foreground. The POINT function actually examines one of the bits in a pattern byte, retuning 0 if the bit is 0, and -1 if the bit is 1. In Listing 7 the cursor moves in a random way inside a circle and the POINT function is used to test when it hits the circle border. Notice that, in line 80, POINT is used as a logical value: Oric Basic takes 01 as TRUE and 0 as FALSE.

We can now integrate some of these features into a more substantial program. The Bottle program draws bottles at varied positions, and in different sizes and colours. The user enters the coordinates of the top left-hand corner of each bottle, within the limits of the 200 x 240 high-resolution screen. The size of the bottle must also be allowed for: this is about 30 x 10 in size one, increasing proportionately up to 150 x 50 in size five. The colour of the bottle is input as an integer between 0 and 7, representing black, red, green, yellow, blue, magenta, cyan and white respectively. The screen background is set to red by line 10, so a bottle of colour 1 will be invisible.

The modules of the program are arranged in the following way: