374 |
|
|
375 |
|
|
376 |
|
|
377 |
Paper |
Unique background textures |
378 |
----- |
------------------------- |
379 |
|
|
380 |
The fragments of nodes seen in buoys are |
The fragments of nodes shown in buoys are |
381 |
generally very similar in appearance. |
generally very similar in appearance. |
382 |
The user could identify the related documents by |
The user could identify the nodes by |
383 |
reading the text of a fragment, but that requires attention. |
reading the text of the fragment, but that requires too much attention. |
384 |
|
|
385 |
Using a unique background texture for each document changes the |
Using a unique background texture for each node |
386 |
|
("virtually printing the node |
387 |
|
on fancy paper") changes the |
388 |
situation dramatically: the user can perceive the identity |
situation dramatically: the user can perceive the identity |
389 |
of the most familiar documents at a glance, |
of the most familiar documents at a glance, |
390 |
even when only fragments are shown. |
even when only small fragments are shown. |
391 |
Furthermore, when moving from node to node, the pre-attentive |
Furthermore, when moving from node to node, the pre-attentive |
392 |
cues of identity help the user maintain a sense of direction. |
cues of identity help the user maintain a sense of direction. |
393 |
|
|
394 |
The background textures are randomly chosen using the identity as a seed. |
The texture should not be |
395 |
That is, each document has a unique backround texture, but the texture |
in any way related to the contents of the document. |
|
is not in any way related to the contents of the document (except |
|
|
that a hash of the contents could be used as an identity of an immutable |
|
|
document). |
|
396 |
That way, the textures in any view are as different as possible, |
That way, the textures in any view are as different as possible, |
397 |
even if the documents are similar. |
even if the documents are similar. [XXX Need to explain a LOT better] |
398 |
Furthermore, the unique background of any document can be instantly drawn, |
|
399 |
as soon as the identity inside the system is known. |
The background textures are generated at run time, |
400 |
|
using the node identity as a seed value to a pseudo-random number |
401 |
The distribution of the textures is designed to be maximally |
generator. Because the algorithm is fixed, a node's texture |
402 |
diverse and recognizable with respect to a rough, qualitative model |
will remain the same between invocations even though the |
403 |
of visual perception. |
texture is not stored anywhere. |
404 |
|
|
405 |
|
The generation of usefully unique background textures |
406 |
|
is not simple - the distribution has to be carefully |
407 |
|
adjusted to produce |
408 |
|
maximally |
409 |
|
diverse and recognizable textures, taking into |
410 |
|
account the properties of human visual perception. |
411 |
For example, backgrounds with random pixels (noise) would all |
For example, backgrounds with random pixels (noise) would all |
412 |
look the same, because the pixels are not perceived individually. |
look the same, because the pixels are not perceived individually. |
413 |
However, shapes and overall colors should be independently random to |
However, shapes and overall colors should be independently random to |
425 |
|
|
426 |
At each pixel, the combined values of the basis textures |
At each pixel, the combined values of the basis textures |
427 |
are used for interpolating between the colors |
are used for interpolating between the colors |
428 |
of a small, randomly chosen palette of *compatible* colors. |
of a small palette of *compatible* colors, randomly |
429 |
|
chosen from a carefully weighted distribution. |
430 |
That way, the colors and shapes are independently random |
That way, the colors and shapes are independently random |
431 |
and the palette can be restricted to light colors to |
and the palette can be restricted to light colors to |
432 |
maintain readability. |
maintain readability. |