OpenEuphoria Manual

8.48 Graphics - Cross Platform

8.48.1 Routines

8.48.1.1 position

<built-in> procedure position(integer row, integer column)

Parameters:

1. row : an integer, the index of the row to position the cursor on.
2. column : an integer, the index of the column to position the cursor on.

sets the cursor to where the next character will be output.

Comments:

Set the cursor to line row, column column, where the top left corner of the screen is line 1, column 1. The next character displayed on the screen will be printed at this location. position will report an error if the location is off the screen. The Windows console does not check for rows, as the physical height of the console may be vastly less than its logical height.

Example 1:

position(2,1)
-- the cursor moves to the beginning of the second line from the top

See Also:

get_position

8.48.1.2 get_position

include std/graphics.e
namespace graphics
public function get_position()

returns the current line and column position of the cursor.

Returns:

A sequence, {line, column}, the current position of the text mode cursor.

Comments:

The coordinate system for displaying text is different from the one for displaying pixels. Pixels are displayed such that the top-left is (x=0,y=0) and the first coordinate controls the horizontal, left-right location. In pixel-graphics modes you can display both text and pixels. get_position returns the current line and column for the text that you are displaying, not the pixels that you may be plotting. There is no corresponding routine for getting the current pixel position, because there is no such thing.

See Also:

position

8.48.1.3 text_color

include std/graphics.e
namespace graphics
public procedure text_color(color c)

sets the foreground text color.

Parameters:

1. c : the new text color. Add BLINKING to get blinking text in some modes.

Comments:

Text that you print after calling text_color will have the desired color.

When your program terminates, the last color that you selected and actually printed on the screen will remain in effect. Thus you may have to print something, maybe just '\n', in WHITE to restore white text, especially if you are at the bottom line of the screen, ready to scroll up.

Example 1:

text_color(BRIGHT_BLUE)

See Also:

bk_color , clear_screen

8.48.1.4 bk_color

include std/graphics.e
namespace graphics
public procedure bk_color(color c)

sets the background color to one of the sixteen standard colors.

Parameters:

1. c : the new text color. Add BLINKING to get blinking text in some modes.

Comments:

To restore the original background color when your program finishes, ( often 0 - BLACK), you must call bk_color(0). If the cursor is at the bottom line of the screen, you may have to actually print something before terminating your program; printing '\n' may be enough.

Example 1:

bk_color(BLACK)

See Also:

text_color

8.48.1.5 console_colors

include std/graphics.e
namespace graphics
public function console_colors(sequence colorset = {})

sets the codes for the colors used in text_color and bk_color.

Parameters:

1. colorset : A sequence in one of two formats.
   1. Containing two sets of exactly sixteen color numbers in which the first set are foreground (text) colors and the other set are background colors.
   2. Containing a set of exactly sixteen color numbers. These are to be applied to both foreground and background.

Returns:

A sequence: This contains two sets of sixteen color values currently in use for foreground and background respectively.

Comments:

• If the colorset is omitted then this just returns the current values without changing anything.
• A color set contains sixteen values. You can access the color value for a specific color by using [X + 1] where 'X' is one of the Euphoria color constants such as RED or BLUE.
• This can be used to change the meaning of the standard color codes for some consoles that are not using standard values. For example, the Unix default color value for RED is 1 and BLUE is 4, but you might need this to swapped. See code Example 1. Another use might be to suppress highlighted (bold) colors. See code Example 2.

Example 1:

sequence cs
cs = console_colors() -- Get the current FG and BG color values.
cs[FGSET][RED + 1] = 4 -- set RED to 4
cs[FGSET][BLUE + 1] = 1 -- set BLUE to 1
cs[BGSET][RED + 1] = 4 -- set RED to 4
cs[BGSET][BLUE + 1] = 1 -- set BLUE to 1
console_colors(cs)

Example 2:

-- Prevent highlighted background colors
sequence cs
cs = console_colors()
for i = GRAY + 1 to BRIGHT_WHITE + 1 do
   cs[BGSET][i] = cs[BGSET][i - 8]
end for
console_colors(cs)

See Also:

text_color bk_color

8.48.1.6 wrap

include std/graphics.e
namespace graphics
public procedure wrap(object on = 1)

determines whether text will wrap when hitting the rightmost column.

Parameters:

1. on : an object, 0 to truncate text, anything else to wrap.

Comments:

By default text will wrap.

Use wrap in text modes or pixel-graphics modes when you are displaying long lines of text.

Example 1:

puts(1, repeat('x', 100) & "\n\n")
-- now have a line of 80 'x' followed a line of 20 more 'x'
wrap(0)
puts(1, repeat('x', 100) & "\n\n")
-- creates just one line of 80 'x'

See Also:

puts, position

8.48.1.7 scroll

include std/graphics.e
namespace graphics
public procedure scroll(integer amount, console :positive_int top_line,
        console :positive_int bottom_line)

scrolls a region of text on the screen.

Parameters:

1. amount : an integer, the number of lines by which to scroll. This is >0 to scroll up and <0 to scroll down.
2. top_line : the 1-based number of the topmost line to scroll.
3. bottom_line : the 1-based number of the bottom-most line to scroll.

Comments:

• New blank lines will appear at the vacated lines.
• You could perform the scrolling operation using a series of calls to puts, but scroll is much faster.
• The position of the cursor after scrolling is not defined.

Example 1:

.../euphoria/bin/ed.ex

See Also:

clear_screen, text_rows

8.48.2 Graphics Modes

8.48.2.1 graphics_mode

include std/graphics.e
namespace graphics
public function graphics_mode(object m = - 1)

attempts to set up a new graphics mode.

Parameters:

1. x : an object, but it will be ignored.

Returns:

An integer, always returns zero.

Platform:

Windows

Comments:

• This has no effect on Unix platforms.
• On Windows it causes a console to be shown if one has not already been created.

See Also:

video_config