Clearing "Clean" & a Select Modify question

[Paul LaFlamme]

Hi All,

Suppose I have 100 X 100 pixel square filled in with Navy Blue.

What I really want is to hollow out the inside of that square so that I leave a 2 pixel blue border.

In my first attempt to do this, I selected Select-Modify-Contract. Instead of pulling in the selection in all directions, it only pulled the bottom up. Why would it do that? There are no options to control direction of contract like when you increase the size of the canvas for example.

My second attempt, I manually selected the inside of the square leaving only a 2-pixel border. That worked ok, but when I pressed Delete, it feathered the edges. I'm looking for a clean cut. I want to leave no color inside the selected area whatsoever. When I pressed Del a second time, it began to clear into the 2 pixel border - the area I do not want to clear.

Thank you for the help!

Paul

[Colin Walls]

When you did the select for attempt #2, had you turned off feathering?

I would use stroking to achieve the result you're after.

[Sky Chaser]

For some very strange reason, you can't use Select -> Modify -> Contract if you have selected the whole image (CTRL-A).

What you can do, is make a fixed-size selection of 96x96 and place it manually where you want it, this shouldn't create a feather. However, stroking a selected empty layer on the inside with 2px, then selecting the contents of the layer and inverting it is probably just as easy.

You should check wether anti-aliasing is off, too.

My guess is that in your first try, you had selected 100x99 pixels, leaving the bottom row of pixels unselected. That's why it only pulled up from the bottom.

Hope that helps :)

[Ed A. Ortiz]

You can use Select > Border, too.

[YrbkMgr]

Colin,

I cannot figure out how you might center a selection.




That's essentially what I was asking in the post below:

YrbkMgr "Can Alpha Channels be aligned relative to the canvass?" 7/24/03 4:41pm </cgi-bin/webx?50@@.1de9ff19/3>

Michael seems to think you can do it, but, I can't find a way.

Peace,
Tony

[Colin Walls]

Yes Tony, I looked at that thread and also failed to see the answer. :-)

[Sky Chaser]

Tony, Colin,

You can center a selection by simply putting 2 guides over the center of your image (1 vert., 1 horiz.) and moving the selection over the guides until it snaps to both. The guides will snap automatically to the center of the image if the current layer is entirely selected or entirely filled.

Then again, I might have misunderstood your meaning. If that's the case: NVM :)

[Colin Walls]

Sky:

I cannot make this work. If I place the guides as you say, I can get the corder of a square selection to snap into the corner of the 2 guides. I can't get it to centre. What am I doing wrong?

[YrbkMgr]

Sky,

I can PLACE a selection, no problem. The issue is, when you want, say a text mask in the lower right hand corner of all images in batch, and the images vary in dimensions. There's no way to center it like you can with a layer.

My workaround, for my specific case, was to create the text layer, align it, select the transparency (ctrl-click), save that as the alpha channel, then delete the text layer.

Works good for text, but a plain selection alignment seems impossible - in an automated fashion across different document sizes.

Colin,

After placing your guides, click on the text layer, then click on the Move tool. Notice that the center of the bounding box has a little circle with crosshairs in it. Snap that to the intersection of the guides.

Peace,
Tony

[Colin Walls]

Tony

Thanks - I understand now. I was trying to locate a selection - this works with a layer. Only wrinkle is that I can see the bounding box, but it disappears while I click and drag the thing around. Anyway I can get the right result now.

[YrbkMgr]

Colin,

I was just explaining how to snap the text to the intersection of the guides. But the easiest way to center text on a canvas is this:

Be on the text layer. Ctrl-A; click on the move tool. Look at the options bar. Done.

Peace,
Tony

[Colin Walls]

Thanks again Tony. I get it. Reason I couldn't use it for a selection is that I never use the Move tool to move a selection. When you've drawn, say, a rectangular marquee, you can just point inside it and move it anyway.

I am slightly more educated.

[Paul LaFlamme]

Thanks everyone for your responses. I figured out why My Select-Modify-Contract was only contracting from the bottom of the image. The answer is actually in the help text. My image was 100 X 125 and I was trying to clear a section out of the middle 100X100 leaving a 2 pixel border.

So I selected the top 100X100 pixel cube on the top of the image.

The PS7.01 help text says that Contract will not work unless the canvas size is larger than the selected area. In my case, the top, left, and right sides were at the edge of the canvas.

The Select-Modify-Contract contracted only the bottom line of the selection block. This is by design. Now my next question is WHY WOULD THEY WANT TO DO THAT? It seems strange, doesn't it? What other commands don't work "normally" if your selection is at the edge of the canvas? I'm going to start a new thread and pose the question.

I still can't figure out why my CUT of the middle square is feathering. Where do you control feathering for the cut command?

Thank you everyone,

Paul

[YrbkMgr]

That worked ok, but when I pressed Delete, it feathered the edges.




Paul,

I've never seen that happen. Do this as an experiment.

Before you actually cut (btw, I presume you mean delete), save the selection as an alpha channel. Then click on that channel in the Channels Pallet. Is it clean there? That will tell you everything.

Peace,
Tony