I’m try turn a image into black&alpha vector image manually. I draw a shape over another shape, but since the top one should be filled by transparency, I’ve use Tool_Options->Fill->Mesh_Gradient and drag those line in Mesh_Gradient to cover this shape, but the bottom one will be displayed.
Hello and welcome to the forum 
I’m not sure what you mean by that.
Do you mean filled with a particular colour or do you mean filled with ‘transparency’?
Either way, if you’re making a vector image by tracing over an existing image, you should create the traced vector shapes with the Fill: Not Filled option in the Tool Options docker so that you can see the raster image underneath them.
Later, you can edit the vector shapes to give them any type of fill that you want.
If you can learn how to use the Bezier Curve Tool, that is very useful for drawing curved shapes that can easily be edited later to adjust their shape.
Adjusting the detailed outline of a vector shape is best done with the Edit Shapes Tool after it’s been selected with the Select Shapes Tool.
Here is a video tutorial for beginners, like yourself, who want to create vector images:
https://www.youtube.com/watch?v=QNXg9H-ru8s
This one may also be useful for you:
https://www.youtube.com/watch?v=yK-H40ELzhE
If you have difficulties, you can ask for more help and advice in a Reply to this topic.
First, thanks for your reply.
Yeah, I mean “filled with transparency”, I just forgot this word until see it.
Fill with transparency, but everything under this transparency shouldn’t be shown – they should be “covered” by transparency since transparency as background – just like covered by white on a white-as-background image.
In this example, the right bear’s left side be shown onto left bear because left one is filled by transparency so it will not cover right bear. But originally left one is higher so these area shouldn’t be appear.
I do use these tools because they seem most fit when draw a regular curve(Want a way to lossless convert but that seem impossible)
The defining property of transparency is that you can see through it so that whatever is underneath is visible.
If you want what you describe, then choosing Fill: Background Colour would work with a background colour of white.
However, as I said:
You can’t ‘lossless convert’ a raster image into a vector image. They are two very different things and the vector representaion can only be an approximation of the raster image.
Oh, I found what I need, the filter mask with “Color to Alpha” does convert every white color to transparency, so I fill with white just like fill with transparency(Although It need some adjustment).
Maybe using the “erase” blending mode?
This topic was automatically closed 3 days after the last reply. New replies are no longer allowed.
