What does Rasterize do?

[ngineergeek]

I was trying to select a circular part of my image and copy and paste it as a a layer. With help from previous posts, I created a mask and once I rasterized the photo I had pasted, I could then copy the selection and paste as a layer. I just want to know what Rasterize is for? I entered a photo and thought it would be a raster by default, but apparently it is treated as Vector graphics?  Thanks in advance as I am new to Affinity today.

[crabtrem]

I am no expert. So forgive me. I was having trouble following what you were doing and why. 

I made this quick video trying to show you what I thought you wanted to do, but I'm not sure?

AD copy and paste selection test 2.mov

 

You can identify the layer type in the layers panel in the parenthesis. 

I believe you are correct in that rasterize will create a pixel layer copy of whatever you have selected.

The only keyboard step you didn't see was the CMD-D to deselect the selection.

Forgive no edits or sound.

 

I'm not sure if this helps you or not.  I'm not sure why you were making the mask, but I may have misinterpreted your requirements completely.

Sorry if I created more confusion.

[R C-R]

When you say you "entered a photo" do you mean you opened a photo file using the File > Open menu item, used the "Place" tool or menu item, or something else?

 

Depending on how you did that, the photo may have been in an image instead of a pixel layer. (Which one it is is indicated in parentheses in the Layers panel.) Images are treated as objects, sort of like vectors. Rasterizing them converts them into bitmaps (pixels) that can be edited.

[Magnus_vb]

I found the term "rasterise" a bit confusing as well. Is't also possible to Rasterise an image that you have opened (not placed)? For me, before "rasterising" an image, you can always change the crop and/or size without loss in quality. After rasterising the cropped area is deleted and it is no more possible to upsize (without loss in quality). The image is "Finalised"   :unsure: (at least in my mind)

[R C-R]

For what very little it is worth, Affinity uses the term "rasterize" for the same thing I have always understood it to mean, that being "convert to a pixel bitmap."

 

What confused me at first about it is in Affinity it always appears in menus as "Rasterize..." By longstanding UI conventions the "..." part indicates this will open a dialog box or similar UI element to choose among various options before any action is taken, just like for the "Open..." & numerous other menu items. It was easy enough to get used to that once I realized the "..." part is apparently meaningless for this menu item, but what took longer to figure out was the difference between a pixel layer & an image one, & that "Rasterize..." is not greyed out for an already rasterized layer.

 

I suspect this might have something to do with a feature yet to be implemented, one that does offer options in a dialog box, but that is just a guess.

[A_B_C]

Hi ngineergeek,

 

maybe these older posts are still useful for a proper understanding of image and pixel layers:

 

https://forum.affinity.serif.com/index.php?/topic/13651-layers-and-masks-concepts/?p=60276

https://forum.affinity.serif.com/index.php?/topic/13815-couple-of-questions/?p=66856

 

Cheers, Alex  :)

[R C-R]

What confused me at first about it is in Affinity it always appears in menus as "Rasterize..." By longstanding UI conventions the "..." part indicates this will open a dialog box or similar UI element to choose among various options before any action is taken, just like for the "Open..." & numerous other menu items. It was easy enough to get used to that once I realized the "..." part is apparently meaningless for this menu item...

I just discovered that there is a reason for the ellipsis ("...") in the "Rasterize..." menu item. When rasterizing a layer with layer effects (fx) applied to it, a dialog box pops up asking if the effects should be preserved or not. That is the only place I have discovered that invokes a dialog box but there may be others.

[vonBusing]

I also reacted at the Rasterise function doing things immediatly without the expected dialogue that the ellipsis should imply.

 

Another situation where the ellipsis could make sense is in documents with bleed. On rasterize, we could have the option to include the bleed area to the rasterized layer/object.

[csbro]

All I want to know is, "What time is it?". 

Raster: A set of horizontal lines composed of individual pixels, used to form an image on a screen.

Why must I "rasterize" the tutorial image below in order to get the "Flood Select" tool to work, albeit temporarily. 

{When I use the FS tool without rasterizing it initially selects a portion of the sky (maybe) then the mountain is selected, then the screen goes blank & after re-painting, the entire image is selected.

After rasterizing the image, the tool selects the sky correctly but then the image goes blank, & after re-painting,  the entire image is selected.}

1. Is "Rasterize" an integral part of the "Flood Tool" process?

2. Why does the document image re-paint & re-select?

[walt.farrell]

2 hours ago, csbro said:

Why must I "rasterize" the tutorial image below in order to get the "Flood Select" tool to work, albeit temporarily. 

{When I use the FS tool without rasterizing it initially selects a portion of the sky (maybe) then the mountain is selected, then the screen goes blank & after re-painting, the entire image is selected.

After rasterizing the image, the tool selects the sky correctly but then the image goes blank, & after re-painting,  the entire image is selected.}

1. Is "Rasterize" an integral part of the "Flood Tool" process?

2. Why does the document image re-paint & re-select?

1. When you have the image open, look in the Layers panel. Do you have a (Pixel) layer or an (Image) layer? If it's an image layer, you need to rasterize because many tools (including Flood Select) work only on pixel layers, not image layers. The kind of layer you will start with depends, to some extent, on how you opened the image. If you followed the Tutorial instruction and used File > Open I would expect it to be a pixel layer, with no rasterization needed.

2. It may depend on how you followed the instructions in the tutorial. The tutorial says to click and drag in the clouds, and keep dragging right to increase the tolerance until the entire sky is selected. If you drag into something inappropriate (too different in color) and increase the tolerance too much, you'll select too much (and possibly the entire picture).

[csbro]

I have done & re-done the lesson many times over. Each time re-checking the process to insure accuracy. If I "swipe" the sky fairly quickly it selects the sky, only to re-paint & select the entire "pixel" layer. 

[walt.farrell]

Sorry, but I can only say it works for me. Perhaps someone else will have an idea for you.

[toltec]

The Flood Select tool is controlled by how far you move the mouse from where you first click. The more you move it, the more it selects. You can see that in the context menu tolerance box.

It can be a bit tricky with some images. 

I would suggest you try using the Selection Brush tool instead. Just paint over the sky. I tried and it only took a couple of seconds.

 

[walt.farrell]

31 minutes ago, toltec said:

I would suggest you try using the Selection Brush tool instead. Just paint over the sky. I tried and it only took a couple of seconds.

That may be more practical for him, toltec, but he's trying to follow the Photo Workbook tutorial on Flood Select, p.  108

[toltec]

13 minutes ago, walt.farrell said:

That may be more practical for him, toltec, but he's trying to follow the Photo Workbook tutorial on Flood Select, p.  108

I know, but he seems to be dragging too much and over selecting with the tolerance setting or there is another issue.

I don't think it's a very good image for the flood select tool, too much grey, but if he tries with the selection tool, he will at least be able to see a 'proper' selection to see that everything works as would normally be expected. If that doesn't work, there is definitely an issue.

Gotta start somewhere and try something ?

[R C-R]

7 hours ago, toltec said:

I don't think it's a very good image for the flood select tool ...

The 10.2 MB flood_select.jpg from the download for the workbook is a very good image for this exercise. Depending on where in the clouds I start the drag, at between about 19 & 26% tolerance, the clouds are easy for me to select without selecting anything else.

The screen going blank suggests there is something wrong with the installed Affinity Photo app.

[csbro]

Considering R C-R's comment I removed & reloaded af but the same thing happened. I then paid closer attention to the "tolerance" %. It seems for this pixel image 33% works. I believe the selection brush would be a lot easier than attempting multiple "swipes" till I got the % right. Perhaps it's like everything else. The more one does it the better one gets. 

Thanks for the input, all. 

[toltec]

14 minutes ago, csbro said:

Considering R C-R's comment I removed & reloaded af but the same thing happened. I then paid closer attention to the "tolerance" %. It seems for this pixel image 33% works. I believe the selection brush would be a lot easier than attempting multiple "swipes" till I got the % right. Perhaps it's like everything else. The more one does it the better one gets. 

Thanks for the input, all. 

Quite right, practice makes perfect. But it is also a matter of selecting the right tool for the job.

Personally, I would not use the Flood Select Tool for that type of image. So much easier with the Selection Brush.