Selection tools
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| Selection tools | Juhana Sadeharju | 30 Dec 15:21 |
| Selection tools | Sven Neumann | 30 Dec 17:17 |
| Selection tools | Raphaël Quinet | 30 Dec 21:37 |
| Selection tools | Juhana Sadeharju | 31 Dec 17:12 |
Selection tools
From: Sven Neumann
GIMP has a bunch of selection tools and they seem to work quite well for a lot of people. I think I know what problems you are refering to but it would help the discussion if you could specify which selection tools you are talking about and how they could be improved.
The Bezier selection tool is good but there should be a polygonal selection tool of CAD type as well.
It is always strange when one says "practically unusable" while many people have used the tools for years. But I have developed audio software and there are the same problems with the selection tools. I simply don't know how people edit audio properly without the tools I have invented -- I use those tools everytime I make a selection. As said, strange.
Some months ago I prepared two tests for GIMP but I'm not sure did I post them at that time. I wanted to ask how GIMP users do the required selections. Maybe there are compilicated tricks which helps in the situation but I prefer to use simple tools directly applicable to the tasks.
Here is an alternative rectangle selection tool:
(1) by pressing the left mouse button, user may drag the (initial)
rectangle,
(2) when pointer is moved on the selection edges and corners,
user may grab and drag the edge or the corner,
(3) selection gets deleted if user pressed mouse button when the
pointer is not on the edges or the corners.
That is all what can be done with the tool. There is no possibility to enlarge the selection the way the current rectangle selection can be enlarged.
The rectangle could be deleted only by clicking outside the rectangle, and the whole rectangle could be moved by grabbing inside the rectangle. When the selection is moved this way, only the selection info is changed and no image data is moved around (as happens with the current selection tools).
The problem with current selection tools are that the selection cannot be re-adjusted in a natural way. Another problem is that the tools fails with large images. That is why in my tool the edges and the corners can be grabbed and dragged. (This problem is more severe in audio editors where zoom ratios are very large.) One cannot do precise edits without re-adjustment possibility.
Crop tool in GIMP has these problem as well. An alternative crop tool would be great.
I took the latest CVS version. If it compiles, we could only check how to get me started for coding these tools.
Regards, Juhana
Selection tools
Hi,
Juhana Sadeharju writes:
Here is an alternative rectangle selection tool: (1) by pressing the left mouse button, user may drag the (initial) rectangle,
(2) when pointer is moved on the selection edges and corners, user may grab and drag the edge or the corner, (3) selection gets deleted if user pressed mouse button when the pointer is not on the edges or the corners.That is all what can be done with the tool. There is no possibility to enlarge the selection the way the current rectangle selection can be enlarged.
The point is that you misunderstood what a selection is. A selection is a mask holding a selection value between 0 and 255 for each pixel in the image. What you see on the GIMP canvas is just the selection border, a line draw along the pixels that are 50% selected. Now if you create a rectangular selection, you alter the selection mask so that it looks like a rectangle. The information about the corner points of the rectangle is not stored anywhere. That's why you cannot edit the selection the way you suggested.
I am not saying that our selection tools couldn't behave differently, but I am saying that it would require a major redesign of how GIMP treats selections. The vectors tool was designed in a way that allows it to work on other shapes than only bezier curves. We might want to base a new rectangles tool on this architecture and perhaps it would even make sense to make this the default rect-select tool.
The rectangle could be deleted only by clicking outside the rectangle, and the whole rectangle could be moved by grabbing inside the rectangle. When the selection is moved this way, only the selection info is changed and no image data is moved around (as happens with the current selection tools).
... unless you press the Alt key.
I took the latest CVS version. If it compiles, we could only check how to get me started for coding these tools.
Well, a good start would be to make yourself familiar with such basic concepts of image editing as selection masks. This is an important feature that we cannot live without. A good way to understand selections is to play with the QuickMask feature. It illustrates selections quite well.
Sven
Selection tools
On 30 Dec 2003 17:17:33 +0100, Sven Neumann wrote:
Juhana Sadeharju writes:
Here is an alternative rectangle selection tool:
[...]
The point is that you misunderstood what a selection is. A selection is a mask holding a selection value between 0 and 255 for each pixel in the image. What you see on the GIMP canvas is just the selection border, a line draw along the pixels that are 50% selected. Now if you create a rectangular selection, you alter the selection mask so that it looks like a rectangle. The information about the corner points of the rectangle is not stored anywhere. That's why you cannot edit the selection the way you suggested.
From my point of view, the fact that the information about the corner
points of the rectangle is not stored anywhere is an internal implementation detail that most users should not have to care about. This is something that we could change later.
For example, take a look at this enhancement proposal from jwz, and
especially the comment from Simon:
http://bugzilla.gnome.org/show_bug.cgi?id=91934
The shape of the selection could remain editable until the user
chooses to apply it. This would be even more useful for ellipses
than for rectangles. And as Simon mentioned in his comment, this
could even improve the usability of the selection tools for GIMP
beginners.
Anyway, as there is already a bug report about how to improve the selection tools, I suggest that Juhana takes a look at it.
-Raphaël
Selection tools
From: Sven Neumann
The point is that you misunderstood what a selection is. A selection is a mask holding a selection value between 0 and 255 for each pixel in the image. What you see on the GIMP canvas is just the selection border
OK. I was writing about a tool which is used to make a selection. When the tool is on, it holds the rectangle as vertex/edge data. When user releases the mouse button, the selection mask is created. When user again grabs a vertex or an edge, the selection mask is undoed.
The selection will still be a mask.
Regards, Juhana
