Krita on Linux as the equivalent to Windows’ Paint

Krita seems like a good replacement for Microsoft Paint. It is sufficiently intuitive to use, even without any exposure to it before.

I use such programs primarily to crop and add frames to screenshots. Even for that relatively simple task, Pinta, the first program I tried, is far too unstable (not to say very unstable). Pinta usually works OK for cropping an image, but any drawing operation very quickly makes Pinta freeze (become unresponsive).

Installation

On Ubuntu 20.04 (Focal Fossa) MATE with Cinnamon:

sudo add-apt-repository ppa:kritalime/ppa
sudo apt-get update
sudo apt-get install krita

If the kritalime/ppa repository causes the system update to fail (e.g., “The repository … is no longer signed”), it can be disabled with:

In “Software & Updates”, tab “Other Software”, uncheck the checked one that includes “kritalime”.

Common operations

Create a new image with the same dimensions as the image in the clipboard

E.g., as a result of cutting out a portion of a larger screenshot.

Do menu Edit → Paste into New Image (shortcut Ctrl + Shift + N).

If there is a dialog box, choose “As Web” (shortcut Alt + W).

(In Windows Paint, this was done by starting with an initial image smaller than the one in the clipboard, say 100×100 pixels, and then pasting in the image. The result was a new image with expected dimensions.)

The content in the clipboard could come from a screenshot by Ctrl + PrtSc in Ubuntu MATE 20.04 (Focal Fossa). Note that this copies both screens on a system with two screens. Or Ctrl + Shift + PrtSc for selecting a part of the screen for the screenshot. Or Ctrl + Alt + PrtSc for making a screenshot of the current window.

Note: These shortcuts changed in Ubuntu 22.04 (Jammy Jellyfish) (the content farms, etc. don’t seem to have discovered it…). Just press the PrtSc key, change the bounding box using the mouse, and Ctrl + C will work for getting a selected part of the screen only the clipboard.

For taking a screenshot (on Linux) of a menu or similar where it normally goes away when the PrtSc key is pressed, see Taking a screenshot of a menu in Cinnamon.

Change image size (e.g., to make space for a frame)

Get image dimensions: Menu Image → Properties. Close the dialog (e.g., by pressing Enter).

Add two times the expected width for the frame plus a margin (e.g., 2×20 + 10 = 50).

Open a new image (Ctrl + N) and select “Custom Document” (usually the default). Fill in the new dimensions in fields “Width” and “Height”. Press Create (or Alt + C).

Paste in the image and select it.

Use the Move tool to center the image (on the left, select “Move Tool” (eight row, second column). Or press “T”.).

It is possible to precisely center the image. This isn’t supported directly for bit images, but we can use a trick for our kind of images here: Set the snap grid size to half the extra size in pixels (as the upper left corner of the image should be on the first grid point in the upper left), in the example here 50 pixels / 2 = 25 pixels. Change the grid size by menu “Settings” → “Dockers” → “Grid and Guides” (if not already enabled). In the right panel, near the bottom, “Grid and Guides” opens (if not already). Change both “X spacing” and “Y spacing” to “25 px”. Check “Show grid” (if not already). The image will not snap, but now the grid marks the exact place where the upper-left corner of the image should be. Move the corner of the image near where it should be and then zoom in order to move it to the pixel-exact place.

Note: Menu Image → Scale Image to New Size (Ctrl + Alt + I) can not be used because it will also scale the image.

Create a frame for an image

On the left, select “Line Tool” (third row, second column).

In “Brush Presets” (on the right, mid), select “b)_Basic-1” (the fifth). (Krita is way too complex for its own good in this instance. Why isn’t the default a solid brush?)

On the right, in “Advanced Color Selector”, click on the colour ring. This will not by itself change the colour. In the three rows below the colour ring, click to select a colour. This will change to colour for subsequent line drawing operations.

Set line width: First select “Line Tool” in the left panel. Then in the toolbar, “Size” (to the right of “Opacity”), click in it to set some size. A drag action will continuously show the line width. It can also be set to an exact size by right clicking (then the line width can be typed in). Finish by pressing Enter. A reasonable size for a frame is 20 pixels.

Draw the frames. To lock in the x or y direction (actually, it is 15° increment), hold down the Shift key and move the mouse a little to lock it into place.

Zoom in and out

The menu commands are menu View → Canvas → Zoom In / Zoom Out. More interesting are the keyboard shortcuts. They are the same as a web browser (Ctrl + “+” and Ctrl + “-“).

More exact control is in the lower right. In the dropdown, the zoom percentage can be typed in. Or, for instance, select “Fit Page” to take maximum advantage of the available screen space.

Freehand circles

On the left, select “Freehand Brush Tool” (in the default configuration (two icons per row), third row, first column). The keyboard shortcut is “B”.

For changing the colour, see above, near “click on the colour ring”.

Straight lines

See section “Create a frame for an image” above, near “On the left”.

Add text

First select the text tool (in the default configuration (two icons per row), first row, second column).

Then make a (square) selection (left click and drag). The size of the selection will determine the size of the text.

Fill in the text in the lower part (it isn’t the first text field; that is for the font…) and press Save and Close.

Se also the YouTube video Krita: How to add text in Krita. Super easy tutorial.

Alternatives

A video reviewing 4M Linux (at 11 min 46 secs) reveals:

• mtPaint
• GNU Paint
• XPaint