Set contone colour for selected region of bitmap

[DD]

With a photo bitmap selected I can right click a colour to "set contone light" or "set contone dark".

I have a black and white bitmap and would like to change black to some other colour but only on a selected region.

Masks don't seem to to be the solution ? but I am a mask virgin.

Maybe setting contone colour is not the correct route.

Any thoughts appreciated.

David

[MarcT]

Hi David,

One way would be to duplicate the image, draw a shape over the region you want to be different and do a boolean intersection with the copied image and the shape.

You can then apply another color on that new cropped image.
Also applying a feather on the top image makes for a better blend in certain situations..

Marc

[gwpriester]

Screen and Color transparency can be applied to colored shapes as Marc suggests. They work slightly in different ways.

[Egg Bramhill]

Just to reiterate Marc's comments:

[DD]

Thank you for all the ideas.

I had a black and white photo of some sums and wanted to make all 4 sigmas red and ended up doing:

1. Ctrl-K clone image
2. Draw 4 shapes to cover the 4 sigmas.
3. Arrange/CombineShapes/AddShapes to make a single shape.
4. Select the one shape ( really 4 ) and the cloned photo bitmap. Then Arrange/CombineShapes/IntersectShapes to make a single clipped photo bitmap of just the 4 sigmas.
5. Right click colour red and set contone colour dark.

I love Xara and this forum.

DD

[PhilM]

Using Masks:
Start with a photo selected
* Change to Region Painter tool
* Paint regions you want to change
* Change to Selector tool
* Clone (this clones only the areas of the photo covered by the mask regions)
* Apply contone colours

(The general model is that when you're in one of the mask or region tools commands like Clone will _affect_ the mask or region that you're drawing and when you're not in one of the mask or region tools commands _use_ the mask or region that is present. Unfortunately the UI doesn't make this very clear.)

Phil

[DD]

Phil.
Thanks that method is quicker AND I've learned something important about regions/masks.

Gary.
I also had a go at shapes with transparency as that would be quick too but I couldn't see a transparency mode that would change "underneath" black to a given colour ?

Again thanks to all.

Dave D

[DD]

Just played some more with transparency...

Cover areas with a red shape and then apply 0% "Colour dodge" or 0% "Screen bleach" to make "underneath" black go red.

So thanks Gary, that's the easiest method, and you can move and reshape the transparent red objects.

[DD]

Just thought I'd share:

Reading again what Phil said about the region tool and clone...

I have now learnt that clone will clone the regions if the region tool is selected.
But that clone will clone the content of the regions if the region tool is not selected.

I also note that with the region tool selected I can nudge the selected regions with the arrow keys.

[Acorn]

Why not just an a sigma from a font, and colour red and drop on top of the image?

Go further, use Latex, and embed code like this into a body Placeholder:

\[\frac{\partial \dot{v}}{\partial t}=l(x,z)[\frac{\partial }{\partial {x}}(\color{red} {\sigma}_{xy}) +\frac{\partial }{\partial {z}}(\color{red} {\sigma}_{zy})] 
\]
<script type="text/javascript" src="http://www.hostmath.com/Math/MathJax.js?config=OK"></script>

Acorn