The controversial eraser tool

**pauland** · 04 August 2011, 09:10 PM

Originally Posted by handrawn

right

so what you are saying is that the line would need to be converted to shape in order for there to be nodes to define the outline that was left after erase?

yes I can see that John, if you are erasing a line's width and not just it's length

Really?

**handrawn** · 04 August 2011, 09:19 PM

Paul - your image does not show erasing a line's [outline's] width - only it's length

I think the point John is making is a good one if we are talking about a true eraser, and not just 'a remover of already exisiting nodes'

**handrawn** · 04 August 2011, 09:21 PM

Hi Phil

yes - there are several ways it could be implemented

**pauland** · 04 August 2011, 09:29 PM

Originally Posted by handrawn

Paul - your image does not show erasing a line's [outline's] width - only it's length

I think the point John is making is a good one if we are talking about a true eraser, and not just 'a remover of already exisiting nodes'

If you are talking about nibbling into a line, then you are right, but really that's not the correct logical operation for an eraser with respect to a line. Effectively an eraser will sever the line if it crosses it. It doesn't just remove existing nodes, it will add nodes to ensure that the line being severed ends at the correct place. You can see that in my example the severed lines have the correct end caps that have been chosen for the line.

If you want to nibble the shape of the line, make it a shape, then nibble. I'll make an example if you wish.

**pauland** · 04 August 2011, 09:33 PM

As others have remarked Xara almost has the required functionality in place. If I drag the eraser across my shapes and lines it leaves a white shape in it's wake. When I let go that shape is essentially subtracted from any editable shapes and lines it crosses.

**handrawn** · 04 August 2011, 09:35 PM

edit - replying here to post #32

no need Paul - that was my starting point too for vector

which was why I was confused at first, until I realised John was taking you at your word and describing what a true eraser would have to do in a vector environment, ie erase anything it crossed over length or width...

a true eraser of lines would erase width as well as length

**covoxer** · 04 August 2011, 09:43 PM

Originally Posted by pauland

that's not the correct logical operation for an eraser with respect to a line.

That's a correct point. But in your video you can see eraser used to remove only fragments of lines. Some of those lines are very wide. And removed fragments don't even intersect their path. So such eraser tool would be of no help in having the illustrated workflow.

**pauland** · 04 August 2011, 09:54 PM

Originally Posted by covoxer

That's a correct point. But in your video you can see eraser used to remove only fragments of lines. Some of those lines are very wide. And removed fragments don't even intersect their path. So such eraser tool would be of no help in having the illustrated workflow.

The video is not of a vector application. It's intended to show the applicability of the eraser tool in an artistic workflow.

**covoxer** · 05 August 2011, 04:53 AM

Originally Posted by pauland

The video is not of a vector application. It's intended to show the applicability of the eraser tool in an artistic workflow.

Exactly. It shows the applicability of the typical bitmap eraser. And the bitmap eraser does not work the way you suggest for the vector. To have a similar workflow we need more sophisticated implementation of the vector eraser than you suggest. And the one you actually suggest will not help you with organic workflow at all.

On the other hand, to be honest, I'm not sure that even bitmap eraser is necessary for the illustrated workflow. You can do the same only using brushes with proper color selections. No?

**pauland** · 05 August 2011, 10:52 AM

Originally Posted by covoxer

Exactly. It shows the applicability of the typical bitmap eraser. And the bitmap eraser does not work the way you suggest for the vector. To have a similar workflow we need more sophisticated implementation of the vector eraser than you suggest.

I can replicate the effects of the bitmap eraser shown in the video using the flash IDE using only vectors. The only differrence between a vector editor eraser and a bitmap editor eraser is that bitmap editors don't have the concept of lines as seperate editable entities. Once they are drawn they are just pixel shapes like everything else. A vector eraser will respect that a line is a joined series of points with a certain thickness and end caps.

There is no trick question about this these vectore erasers are in existence and work just as you saw in that video. The whole point about the video is that the artist has a very fast, organic workflow that Xara doesn't have at present.[/quote]

And the one you actually suggest will not help you with organic workflow at all.

We must be watching differrent videos. I'll let others judge.

On the other hand, to be honest, I'm not sure that even bitmap eraser is necessary for the illustrated workflow. You can do the same only using brushes with proper color selections. No?

Yes, a brush tool, coupled with an eraser does work. It's the equivalent of the bitmap workflow - erasing brush generated shapes rather than bitmaps. I haven't ever suggested the need for using bitmaps for that workflow.

In flash, the brush tool is drawn across the drawing space and it dynamically creates a shape that encapsulates the area that the brush is moved over. When the eraser tool is dragged, it creates a shape that again encompasses the area over which the eraser has moved. The eraser shape remains visible as the eraser is dragged. When the mouse is released, the shape created by the eraser is subtracted from the shapes and lines that are under it.

A brush tool, plus colour and transparency selections are the equivalent of the artists paintbrush or crayon.