OP Art Picture Gallery

back Information

copy of
Movement in Squares,
Bridget Riley 1964,
by Frank Vollbrecht, Buettgen, 2000

Initial Picture
Based on the square of the left upper corner all other squares, which are distorted, are online computed and stored in a bidirectional list. The drumlike distortion of the first row is computed by the following formular:
squarewidth*SQRT( SIN( distance_from_gap / drumdiameter ) )
All other squares are copied from the bidirectional list and placed into according positions. The mentioned formula produces a quite good distortion which can be compared with the original picture. For any modifications of the initial picture (for example by shifting the vertical gap or adding a second gap) the dynamic list is newly computated via the upper formula.

shifting the gap
By drag&drop or clicking at positions near by the upper edge of the picture the gap can be moved horizontically. There are positions of the gap near by the edge of the picture where the gap will jump back to the initial position.

second gap
If you click at positions near by the right edge of the picture you can generate a second, horizontal gap. This gap may be shifted by drag&drop in the same way as the vertical gap. When reaching certain positions at the upper or lower edge of the picture the second gap will be automatically removed. By drag&drop in the crosspoint of both gaps you may shift both gaps simultanously. Clicking the gaps will produce a fast picture sequence (< 1 s) which contains a wavelike distortion of the whole picture.

faults
If you remove the mouse out of the picture a short picture is generated which shows faults. Afterwards an automatical sequence is called , which is enabled for some minutes. You may shorten this automatical sequence by placing the mouse into the focus of the picture. Then this sequence will stop in about 30 s.

examples for the automatic sequence

The automatic sequences show different distortions with circular functions which are presented in a movie like sequence.Several parameters are controlled by chance:
arch of surface (kind, strength, backward or forward)
direction point, distance
strength of arch
pace of movement

black squares
By pressing black squares with the mouse (without moving!) you may change the order of squares. Depending on the position of the mouse (left side, centre or right side of the picture) pressing will result in different modifications, which will immediately stop, when you move your mouse or finish the press-operation.

white squares

By hiting or pressing white squares colored variations are generated by chance. These variations remain stable for the automatic sequence, when leaving the focus of the picture with your mouse.

back

Initial Picture	Based on the square of the left upper corner all other squares, which are distorted, are online computed and stored in a bidirectional list. The drumlike distortion of the first row is computed by the following formular: squarewidth*SQRT( SIN( distance_from_gap / drumdiameter ) ) All other squares are copied from the bidirectional list and placed into according positions. The mentioned formula produces a quite good distortion which can be compared with the original picture. For any modifications of the initial picture (for example by shifting the vertical gap or adding a second gap) the dynamic list is newly computated via the upper formula.
shifting the gap	By drag&drop or clicking at positions near by the upper edge of the picture the gap can be moved horizontically. There are positions of the gap near by the edge of the picture where the gap will jump back to the initial position.
second gap	If you click at positions near by the right edge of the picture you can generate a second, horizontal gap. This gap may be shifted by drag&drop in the same way as the vertical gap. When reaching certain positions at the upper or lower edge of the picture the second gap will be automatically removed. By drag&drop in the crosspoint of both gaps you may shift both gaps simultanously. Clicking the gaps will produce a fast picture sequence (< 1 s) which contains a wavelike distortion of the whole picture.
faults	If you remove the mouse out of the picture a short picture is generated which shows faults. Afterwards an automatical sequence is called , which is enabled for some minutes. You may shorten this automatical sequence by placing the mouse into the focus of the picture. Then this sequence will stop in about 30 s.
examples for the automatic sequence	The automatic sequences show different distortions with circular functions which are presented in a movie like sequence.Several parameters are controlled by chance: arch of surface (kind, strength, backward or forward) direction point, distance strength of arch pace of movement
black squares	By pressing black squares with the mouse (without moving!) you may change the order of squares. Depending on the position of the mouse (left side, centre or right side of the picture) pressing will result in different modifications, which will immediately stop, when you move your mouse or finish the press-operation.
white squares	By hiting or pressing white squares colored variations are generated by chance. These variations remain stable for the automatic sequence, when leaving the focus of the picture with your mouse.