Let’s spray everything

I added new feature to spray –  spraying bitmap images (textures). Thanks to the KDE you can load plenty of image formats. It starts with Qt QImage supported file formats and continue with KDE supported file formats (psd, xcf to choose the most used ones). Let’s be the mentor for you for a while and teach you how can you do nice things. Let’s start with autumn wallpaper.


You need svn copy of Krita (how to build koffice ) and  some leafs textures (e.g. I used this one , found in wikipedia by Kubuntiac ). The texture has alpha channel, it is png file. That is important so that it looks cool. I scaled that texture to 192×118 px and named it leaf2.png.

Spraying bitmaps works nicely with objects that are cut from some pictures, e.g. some kde hackers on planet have their faces properly cut from photos. It is good example object for spraying.

Some random KDE hackers from planet

In Krita you select spray brush and go to options. In Particle Type you select Spray object to image. Then you select the image within the dialog (Open The File, locate leaf2.png on disk and click ok). In brush size you can specify with particle number — how many images will be sprayed per dab (something like per mouse move event:) ) but what I changed there is spacing to 1.0, so that the brush reacts quicker and with less density. In Color dialog check random HSV and move hue to value 40, saturation to -40 and value leave intact. Here you can experiment. Experiment with scale and brush size too. Brush size can be changed by pressing shift and moving with mouse left and right on the canvas. It was added lately and it is quite handy.

Let’s look at some pictures. This autumn image was made with the leaf texture I mentioned above and one other leaf texture. HSV trasformation nicely changes the texture so you get rich colorful image with just one or two textures.

Spraying leafs - HSV transformation useful

Filters can be useful when painting, here is post-processed version (I used auto-contrast filter). It has different mood, more like some cartoon, illustration style :)

And one for upcoming winter. I did this one with snow flakes. Those are used as textures. Clouds done with feature I wrote about last time.

Snowing [done with spray]

This feature is present in other apps in some ways too. I don’t have Photoshop or Corel Painter, I never used them before but Boud told me that similar feature is called image hose in Corel’s Painter. In GIMP similar feature is called brush pipe.

Developing future

I have to polish the GUI, optimize the algorithm so that more and big images can be sprayed more faster. I plan to improve the particle settings, add more control to rotation to the user’s hands (tablet support, etc. )


How do you see it? Do you like it? What would you add to the spraying of bitmaps?

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7 Responses to Let’s spray everything

  1. andrea says:

    looks really cool, especially the leaf one, thanks!

  2. Kubuntiac says:

    This works great Lukas, *thankyou*!

    The interface to it is simple and powerful, especially the whole sliders to add randomness to things like the opacity and colour. This is a feature that is both impressive to see, but also can be used in a very wide range of ways, for example painting skin, which is not one flat colour, but really a collection of subtly varied colours.

    In many ways, other than optimisations, this feature seems fully complete already, but if I were to ask for just one thing, it would be the ability to load in more than one image and have particles either cycle through them, or pick one at random each time. For example, you could have pictures of 5 different types of leaf in an autumn picture.

    You’ve done such a great job with this though, that if it stayed exactly like it is, I’d be a very happy camper. :)

  3. shamaz says:

    Really well done !! :)

  4. Kubuntiac says:

    Hey, another idea would be to have a checkbox that made the particle’s direction face the same way as the brushstroke, letting you create effects like ( http://img121.imageshack.us/img121/3600/rect4814.jpg ) but with raster images.

    Seems to me that ideally, almost every variable of the spray brush would benefit from a checkbox for tablet pressure, and a slider for variation (like HSV now).

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