Sketchblock selecting and saving part of an image

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JosDuchIt

Posted on: 2014/7/6 19:55 #1

Just can't stay away

I don't see how you can do this
- loading an image
-selecting a rectangular part of it (a square part will do too, using the select rectangle tool always reverts to a square)
- saving that selection (or have it in clipboard)
- reload only that part and continue to work on it

What trick do i miss ?

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/7 0:17 #2

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@JosDuchIt

Glad to hear you giving SB ago!

Quote:

I don't see how you can do this
- loading an image
- selecting a rectangular part of it (a square part will do too, using the select rectangle tool always reverts to a square)
- saving that selection (or have it in clipboard)
- reload only that part and continue to work on it

What trick do i miss ?

If you've updated to 2.6 then you're missing the Copy Selection item in the Edit menu.

Ways to do this:

1. In 2.6 select the area you want using the selection tools, choose Menu->Edit->Copy Selection, this will copy the smallest rectangular area that surrounds your slected area, which can any shape, into the clipboard as a 32bit image.

2. Choose Menu->Misc->CopyBox and drag select the raea you want, this copies a rectangualr box from one layer into a new layer. You can than save that by Menu->Layers->Export Layer or use Menu->edit->Copy to copy to the clipboad.

3. Choose Menu->Image->Resize Image resize image to discard the uninteresting parts. (hardest to do).

Blender For OS4.x : Blues : Walker Broad

JosDuchIt

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/7 16:38 #3

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@broadblues

Thanks for help.

Method 2 worked without problem
I got a crash using method 1 & 3 (saved the crashlog)
I am not sure i used method 3 correctly

Quote:

Choose Menu->Image->Resize Image resize image to discard the uninteresting parts. (hardest to do).

When menu was chosen you get a "move" (hand) cursor (just as with the "move tool, and i positioned the chosen part in the middle of the visible area.
Then tried to save ( i did not discard anything- don't see yet how) using project/Save as/ menu
then got the crash

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 2:24 #4

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@JosDuchIt

email those crash logs please andy@broad.ology.org.uk

Quote:

When menu was chosen you get a "move" (hand) cursor (just as with the "move tool, and i positioned the chosen part in the middle of the visible area.
Then tried to save ( i did not discard anything- don't see yet how) using project/Save as/ menu
then got the crash

No I don;t think you did

Not unless you already had the move tool selected.

The reason I said option 3 was hard to do was because you have to put in the numbers, there is no drag borders etc.

You should have seen a popup window with the various paramters for the image resize options.

Blender For OS4.x : Blues : Walker Broad

JosDuchIt

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 11:03 #5

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@broadblues

Method 3 works OK, it is harder indeed. Is having X,Y info something planned ? ( some raster would allready do)

Export can presently only save in ILBM. Do you have priorities here?
A format that our (free) vectorising SW can handle would be nice.
Xtrace can handle ILBM (but is shareware) , autotrace and potrace can not.

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 11:41 #6

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@JosDuchIt

Quote:

Method 3 works OK, it is harder indeed. Is having X,Y info something planned ? ( some raster would allready do)

I do need to add something to the GUI to allow a small preview so you can see how the resize works, it's not quite design for the job you want though.

There also Method 4

Use the Menu->Layers->Scale / Resize Layer. Choose the Crop Expand Layer options then you can drag the edges to fit the area you want to keep.
You can then use Menu->Layers->Export Layer

Quote:

Export can presently only save in ILBM. Do you have priorities here?
A format that our (free) vectorising SW can handle would be nice.
Xtrace can handle ILBM (but is shareware) , autotrace and potrace can not.

Have you installed PIL the Python Imageing Library? THis adds quite arange of output formats.

The sketchblock version 3.x series may well have a loader / saver module API as using 32ILBM via PIL discards the high dynamic range colour info.

Thanks for the GR reports.

They are both crashing on attempts to allocate memory from the main Pool. Were you short of memory at the time?

I've seen these crashes very very occasionally, I think there might be a memoery trash / buffer under / overrun somewhere that I need to track down.

BTW the GR report you got on saving is actually loading!

Blender For OS4.x : Blues : Walker Broad

JosDuchIt

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 19:34 #7

Just can't stay away

@broadblues

Thanks for the great PIL suggestion.
I was able to select part of an image now , saved as a BMP file wich potrace accepted

About my crashes:
I used to launch Sketchblock from ContextMenus. I launch it now from its icon on WB. I id not encounter Grimreaper any more, but stil encounter freezes that i can't report on easily.

I tried method 4 but
- moving and sizing the cropframe, to frame the part you want is difficult : the dragging of one side affects the perpendicular side. To move the cropframe, without changing its dimensions, the topright edge has to be used.
- some times the cropframe does not appear

Can you be more precise how to use this method?

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 23:05 #8

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@JosDuchIt

Quote:

I tried method 4 but
- moving and sizing the cropframe, to frame the part you want is difficult : the dragging of one side affects the perpendicular side. To move the cropframe, without changing its dimensions, the topright edge has to be used.
- some times the cropframe does not appear

Can you be more precise how to use this method?

Disable the lock aspect check box then all sides move independantly.

Once every now and again the window updates ftare the frame has been drawn, so over writes it. The mouse pointers still change state "hand" to "left right arrows" etc so you can just drag te frame slightly and it will reappear.

Blender For OS4.x : Blues : Walker Broad

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/8 23:35 #9

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@JosDuchIt

Quote:

About my crashes:
I used to launch Sketchblock from ContextMenus. I launch it now from its icon on WB. I id not encounter Grimreaper any more, but stil encounter freezes that i can't report on easily

That's interesting. I mostly start it from filer. It migt be worth checking the stack to see if it is any different (in Ranger). SketchBlock does have a stack cookie so it shouldn't be , you never know though.

As to te freezes, how much memory do you have? How large an image are you editing and how many at once? The only time it freezes for me is when I max out my memory, with swap enabled SketchBlock will operate with a small amount of swap memory, but large allocations can go past the "safe limit".

[edit]
It appears the syack cookie dropped out of the source when I replcaed my memory system. So I just put it back. The icon has 80000 set and SB is using 45k at idle after start up, so make sure your your minium stack is more than 80k if not starting from icon. Hoever I don't think the crashes you repotr are stack related, much too consistent.

Edited by broadblues on 2014/7/9 0:03:55

Blender For OS4.x : Blues : Walker Broad

JosDuchIt

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/9 8:13 #10

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@broadblues
My machine is a SAM 460ex with Ranger reported memory size 2147483648 Bytes

I am editing one file at a time
The same image is used in 2 formats for the reported tests
I used the outputs of my scanner for the same page as a .jpg file of 1530704 bytes and as a tiff file of 177498 bytes.
(I am rather surprised of the size differences.)
In my latest tests i used the tiff file.
It is probably so that the crashes occured for the jpg file.
As i changed using the tiff file nearly (?) simultaneously as swiching the launch method form contextmenus to WB icon, that leaes 2 possible causes.

Stack:
launched form WB Icon min 0 size 81912 used 47852
launched form ContextMenus : idem

Maybe the freezes i saw are due to manipulation sequences of unexperienced user, misinterpreting instructions? I'll report when i can reproduce them.

broadblues

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/9 12:03 #11

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@JosDuchIt

Quote:

My machine is a SAM 460ex with Ranger reported memory size 2147483648 Bytes

Okay so a 2Gb machine then, you are not going to be using swap at all.

Quote:

The same image is used in 2 formats for the reported tests
I used the outputs of my scanner for the same page as a .jpg file of 1530704 bytes and as a tiff file of 177498 bytes.
(I am rather surprised of the size differences.)

It's a little odd that the tiff is smaller than the jpeg but makes no odss to SketchBlock. What's important isn't the size of the image file but the dimensions of the image.

For the simplest image SketchBlock uses 32bytes per pixel (16 for the layer, 16 for the merged image buffer) that will seem like alot but SketchBlock works with HDR colour so the cost is memeory consumption gainst more colours resolution / smoother gradients, and faster prcessing because no type conversion is needed.

But unless your scans are really enormous or you are running other high memory consuming apps at the same time there should be a problem.

Quote:

Maybe the freezes i saw are due to manipulation sequences of unexperienced user, misinterpreting instructions? I'll report when i can reproduce them.

You could be doing something very different to what I have tested, so yes please do report any reproducacble sequences that end in a lockup.

Blender For OS4.x : Blues : Walker Broad

JosDuchIt

Re: Sketchblock selecting and saving part of an image

Posted on: 2014/7/9 16:50 #12

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@broadblues

The image i used most has dimensions 3437x2409
I may have had occasions where the file was loaded 2 or 3 times

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