Eraser question

[jw2004]

If the layer use transparency, when use the eraser tool to erase some area, PL change the pixel's alpha to 0, the r,g,b were not changed, this sometimes make some trouble, I want to make these pixel rgba = 0,0,0,0, it seemed there is no simply way to do that.

I have a suggest, since when the layer does not use transparency, the eraser tool use the background color to fill the area, why not use the backgroud color too when layer use transparency?

Another question, when the foregroud color or backgroud color set to transparency, the brush tool can't do nothing, maybe PL think it's meaningless, but I think it is meaningful, use transparency color to paint equal to erase, maybe we can use this function to make special effect.

[Martin Huber]

If the layer use transparency, when use the eraser tool to erase some area, PL change the pixel's alpha to 0, the r,g,b were not changed, this sometimes make some trouble, I want to make these pixel rgba = 0,0,0,0,(...)

Why do you want to do that?

I have a suggest, since when the layer does not use transparency, the eraser tool use the background color to fill the area, why not use the backgroud color too when layer use transparency?

That's in contrast to the wish of many users who want to keep the color information in transparent areas.

Martin

[Eurgail]

That's in contrast to the wish of many users who want to keep the color information in transparent areas.

Like me, i found it pretty often very useful, that the information is not lost.

@jw2004: where do you have trouble?

[jw2004]

Keep the color information and erase the color information are equal importance, keep the color information is not always the right choice.
In fact, PL has a inner possibility to give us the chance to keep or erase color information.

eraser.png

When use eraser tool, PL give the R,G,B,A channel option, but regardless the R,G,B,A option, PL always keep R,G,B information
The logical behavior is follow the R,G,B,A channel option:
1. if check the R,G,B checkbox, Eraser tool erase the R,G,B;
2. if uncheck the R,G,B checkbox, Erase tool keep the R,G,B

[jw2004]

And if you want only erase R channel, you can check the R and A channel, and so on.

[bkh]

The logical behavior is follow the R,G,B,A channel option:
1. if check the R,G,B checkbox, Eraser tool erase the R,G,B;
2. if uncheck the R,G,B checkbox, Erase tool keep the R,G,B

That might sound like a logical option, but keep in mind that the first variant still must not change the RGB values if the pixel is not fully erased (e.g., when using a soft eraser, an eraser with intensity below 100%, or an eraser using anti-aliasing, so basically all erasers except perhaps hard rectangular ones)? Filling fully transparent pixels with the bg colour wouldn't be a problem, of course.

Also, you'd probably want to remember two tool settings, one for layers with transparency (where some people may want to retain the RGB values), and one for layers without transparency, where most people will want to erase all channels.

But the question remains why it is important to erase RGB values as well. The only reason I can see is that images with lots of transparency will use less disk space. For that reason, PL will erase such pixels when saving as PNG, for example, but afaik, PLD files retain that information.

If there are good reasons for it, I wouldn't mind if PL just filled completely transparent pixels with whatever colour – some of PL's tools already behave that way. Thus if one wants to be able to un-erase parts of an image, a layer mask seems to be the better approach, anyway.

Cheers

Burkhard.

[jw2004]

User's requirement is widely variety, don't replace user's decision. the better way maybe set the mostly case as the default choice.
Since PL can give the option, why not let user give decision?

Since the channel option is useless for eraser tool, why the PL give the channel option for eraser tool ?

And the behavior (channel option) of eraser obvisous differ from other tools, why not let the behavior keep consistent ?

[Martin Huber]

(...)

You still didn't say why you need that.

Martin

[jw2004]

(...)

You still didn't say why you need that.

Martin

for example:

I open a image, and erase some area, but when I use channel to selection to get some selection, the result is not I want
1. orginal image

1.jpg

2.do cutout

2.png

3.channel to selection

2015-06-02_06h57_24.png

Do you think the selection is what I want?
Obviously, the selection is useless for me.

[jw2004]

If there has some way to get the same result as photoshop, please give some demo.

In fact, the hidden color information interference many function, for example, the histogram still stat the transparent pixel, the result obviously is not good for me.

2015-06-02_07h13_56.png

[Eurgail]

Do you think the selection is what I want?
Obviously, the selection is useless for me.

But what did you want? Just the car? Why? If you use the selection for a woring layer it's better to have all colour informations left...just if you change the car mask. Where does the additional information distorb you?
Otherwise there are workarounds available to really get only the car, but for a fast erasing i found it very often more usefull, that the colour information remains.

In fact, the hidden color information interference many function, for example, the histogram still stat the transparent pixel, the result obviously is not good for me.

That's not true; i tried it and the historgramm changes. (Except if you have the working layer panel opened, that does not refresh automatically. There you have to select another layer and backwards to get the new one. Perhaps there could be an automatic refresh?)

P.S.: You would get your result also in the channels panel, when you send all channels to mask.

[jw2004]

Photoshop did not keep the color information many years, can we say, photoshop is wrong?

If someone like keep color information, give him a way to implement,
If someone does not like keep color information, give hime a way to implement too.

[Eurgail]

Photoshop did not keep the color information many years

Has it changed?

[quote="jw2004"can we say, photoshop is wrong?[/quote]
Why not?

If someone like keep color information, give him a way to implement,
If someone does not like keep color information, give hime a way to implement too.

Already existing!?

[Martin Huber]

(...)
3.channel to selection
(...)
Do you think the selection is what I want?
Obviously, the selection is useless for me.

So "Channel To Selection" should take into account transparency. I will change that.

In fact, the hidden color information interference many function, for example, the histogram still stat the transparent pixel, the result obviously is not good for me.

It's so as Eurgail said: the Histogram doesn't show transparent pixels.

Martin

[Martin Huber]

That's not true; i tried it and the historgramm changes. (Except if you have the working layer panel opened, that does not refresh automatically. There you have to select another layer and backwards to get the new one. Perhaps there could be an automatic refresh?)

What do I have to do to reproduce that? Can you send as a small sample PLD?

Martin