ezxdisp

  1. ezxdisp
    1. Description
    2. Author
    3. Requirements
    4. Documentation
      1. Initialize/Finalize a window
      2. Update the graphics in the window
      3. Erase the graphics in the window/layer
      4. Get the pointer coordinates
      5. Draw 2D graphics
      6. Draw 3D graphics
      7. Event handling
      8. Miscellaneous functions
      9. Colors
    5. Examples
    6. Changelog
    7. License

Description

A simple graphics library for X11.

Author

n-sibata and Morihiko Tamai, packaged for CHICKEN by felix winkelmann.

Requirements

easyffi

Documentation

ezxdisp is a simple graphics library for 2D/3D graphical applications. (The official distribution can be found here).

Initialize/Finalize a window

[procedure] (ezx-init SIZE_X SIZE_Y WINDOW_NAME)

This procedure returns a EZX object all other procedures accept.

[procedure] (ezx-quit EZX)

Update the graphics in the window

[procedure] (ezx-redraw EZX)

Erase the graphics in the window/layer

[procedure] (ezx-wipe EZX)
[procedure] (ezx-wipe-layer EZX LAYER)

LAYER should be an exact integer between 0 and 8.

Get the pointer coordinates

[procedure] (ezx-sensebutton EZX)

Returns the current pointer coordinates as three values: BUTTON, X and Y

[procedure] (ezx-pushbutton EZX)

Block until an event is received. Returns three values: BUTTON, X and Y

The BUTTON result is 1, 2 or 3 for the first, second and third mouse button, respectively. The button number is additionally bitwise OR'd with 8 if the shift key is pressed and with 16 if the control key is pressed.

Draw 2D graphics

[procedure] (ezx-point-2d EZX X Y COLOR)
[procedure] (ezx-line-2d EZX X0 Y0 X1 Y1 COLOR WIDTH)
[procedure] (ezx-lines-2d EZX POINTS COLOR WIDTH)
[procedure] (ezx-poly-2d EZX POINTS COLOR)

The POINTS argument should be an SRFI-4 s32vector of the form [X1 Y1 ... Xn Yn] where X and Y are the coordinates of each point.

[procedure] (ezx-rect-2d EZX X0 Y0 X1 Y1 COLOR WIDTH)
[procedure] (ezx-fillrect-2d EZX X0 Y0 X1 Y1 COLOR)
[procedure] (ezx-circle-2d EZX X0 Y0 R COLOR WIDTH)
[procedure] (ezx-fillcircle-2d EZX X0 Y0 R COLOR)
[procedure] (ezx-str-2d EZX X0 Y0 STRING COLOR)

Draw 3D graphics

[procedure] (ezx-set-light-3d EZX EX EY EZ)
[procedure] (ezx-set-view-3d EZX EX EY EZ VX VY VZ M)
[procedure] (ezx-c3d-to-2d EZX SX SY SZ)

Returns two values, DX and DY.

[procedure] (ezx-line-3d EZX X0 Y0 Z0 X1 Y1 Z1 COLOR WIDTH)
[procedure] (ezx-str-3d EZX X0 Y0 Z0 STRING COLOR)
[procedure] (ezx-poly-3d EZX POINTS HX HY HZ COLOR)
[procedure] (ezx-circle-3d EZX X0 Y0 Z0 R COLOR)

The POINTS argument should be a SRFI-4 f64vector containing the X, Y and Z coordinates of each point.

Event handling

[procedure] (ezx-next-event EZX)

Removes the next event from the event queue and returns the event-specific information. If there is no event data in the event queue, this function blocks until the next event occurs. The procedure returns 5 values: the type of the event, the X- and Y-coordinates of the mouse pointer at the time of the event, the button- or keyboard-state mask and the button- or key-code of the event.

The following variables contain the event-types that may occur:

These button-codes are defined:

Code Button
1 left
2 middle
3 right
4 wheel up
5 wheel down

State mask values that may be returned:

Mask State
1 shift key
2 control key
4 left button
8 middle button
16 right button

For keyboard events, some special keys will return a platform independent keycode:

Home #xff50
Left #xff51
Up #xff52
Right #xff53
Down #xff54

The result values will be undefined for events for which they are not used. This table summarizes what results are valid:

Event Results
ezx:CLOSE
ezx:BUTTON-PRESS ezx:BUTTON-RELEASE x, y, state, k/b
ezx:KEY-PRESS ezx:KEY-RELEASE x, y, state, k/b
ezx:MOTION-NOTIFY x, y, state

Miscellaneous functions

[procedure] (ezx-select-layer EZX LAYER)

Focuses on the layer.

[procedure] (ezx-raise-window EZX)

Raises the window.

[procedure] (ezx-window-name EZX STRING)

Sets a name of the window.

[procedure] (ezx-set-background EZX COLOR)

Sets the background color of the window.

Colors

[procedure] (make-ezx-color R G B)

This procedure returns a "color object", which is internally encoded as a f64vector. The red, green and blue components should be between 0 and 1.

Examples

(define ezx (ezx-init 100 100 "Hello, ezxdisp"))
(ezx-set-background ezx (make-ezx-color 1 1 1))
(ezx-fillcircle-2d ezx 50 50 25 (make-ezx-color 1 0 0))
(ezx-redraw ezx)

(let loop ()
  (let-values (((b _ _) (ezx-pushbutton ezx)))
    (loop)))

(ezx-quit ezx)

A more elaborate example is in the egg distribution in a file named 3d_clock.scm, which displays an animated 3D-clock.

Changelog

License

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as
 published by the Free Software Foundation; either version 2 of the
 License, or (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA