Re: Drawing in images?

[MON KEY <monkey@sandpframing.com>]

While examining dragbox2.el it occurred to me that an alternative way to
set a crop would be to use emacs window... er actually 5 windows!

                                                                 68.
  _________________________________________________________________
 |                             !                     |             |
 | window1                     !                     |    window4  |
 |                             !                     |             |
 |                             !                     |             |
 |                            \|/                    |             |
 |---------------------------------------------------|             |
 |           |                /!\                    |             |
 |           |                 !                     |             |
 |           |          Y-axis !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |        window5  !                     |             |
 |~~~~~~~~~~>|<~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~>|<~~~~~~~~~~~~|
 |           |                 !       X-axis        |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                 !                     |             |
 |           |                \!/                    |             |
 |           |-----------------------------------------------------|
 |           |                /!\                          window3 |
 |           |                 !                                   |
 |           |                 !                                   |
 |           |                 !                                   |
 |   window2 |                 !                                   |
 |___________|_________________|___________________________________|
                                                                 68^


* Assume that the image to be cropped/bounded is in window5.

* Assume that all windows have a ~1-3 pixel border.

* Assume that window1, window2, window3, window4 can _only_ be
expanded contracted
  on the axis indicated.

* Assume that window 5 is the only window that can be
expanded/contracted on both axis.

* Assume use of a library such as Drew Adams' DoReMi or equivalent.

* Assume Y-axis -> Up/Down expansion/contraction

* Assume X-axis -> Left/Right expansion/contraction

Window1 can expand/contract only along the Y-axis
Window2 can expand/contract only along the X-axis
Window3 can expand/contract only along the y-axis
Window4 can expand/contract only along the X-axis

Window5 can expand/contract along both the X-axis and Y-axis.
Window5 can recenter/reset the image along both the X-axis and Y-axis.

Shouldn't `posn-object-width-height', `posn-window', `posn-area' etc.
get one reasonably accurate pixel coardinates for a crop?

If so, doesn't this give us visual feedback without need of external calls, SVG
overlays, GTK wonkery etc.?

Also, a novel idea for doing image rotation using artist.el
as influenced by Unpaper's "Virtual Bar":
(URL `http://unpaper.berlios.de/img/deskew-detail1.png')
(URL `http://unpaper.berlios.de/img/deskew-detail2.png')

Which skews an image against a "Virtual Line" by calculating the skew against
some baseline (x-axis, y-axis, both) i.e. the radian as the virtual line's
deviation from "square".

    Emacs window (preferably in a dedicated frame)
 +--------------------------------------------------------60.
 |                                                         |
 |    +-----------------------------------------------+    |
 |    |                     .                         |    |
 |    |                    /                          |    |
 |    |                   /                           |    |
 |    |                  /                            |    |
 |    |                 /                             |    |
 |    |                /                              |    |
 |    |               /                               |    |
 |    |              /                                |    |
 |    |             / <-Virtual Line                  |    |
 |    |            /                                  |    |
 |    |           /                                   |    |
 |    |          /                                    |    |
 |    |         /                                     |    |
 |    |        /                                      |    |
 |    |       /                                       |    |
 |    |      /                                        |    |
 |    |     /                                         |    |
 |    |    /                                          |    |
 |    |   /                                           |    |
 |    |  .                                            |    |
 |    |                                               |    |
 |    |                                               |    |
 |    |                                               |    |
 |    |                                               |    |
 |    |                                               |    |
 |    |                                               |    |
 |  Y |                                               |    |
 |    |       A Skewed Image (needs rotating)         |    |
 |    +-----------------------------------------------+    |
 |      X                                                  |
 +--------------------------------------------------------60.

s_P