Rasterisation makes blurry images

[ygoe]

I've got a screenshot with text and sharp edges. Everything's good. Then I want to place it in a Publisher document onto an existing image of a tablet that's seen from the side. The screenshot needs to be aligned with the black tablet screen.

The screenshot is exported unscaled as .png bitmap image. It's a raster format. When I use the grid warp tool on it, the assistent performs a rasterisation of the screenshot. That makes it very blurry. Why? It is already a raster image. No need to mess with it and alter its resolution in any way. Also, why can't that rasterisation maintain the image's sharpness?

(Publisher 1.7.1 on Windows 10)

[Jon P]

Hi ygoe,

Can you clarify which exact tool you are using, the Mesh or Perspective warp tool?

I've used both of them on some images and it doesn't seem to rasterise or effect the quality, any chance of you attaching the image you are using?

Thanks

[ygoe]

Easy. Just make a screenshot of this forum page, save it unscaled as PNG and drag it into the Publisher document. Then select the image, switch the the Photo persona and select any of the warp tools. The assistant kicks in and tells you it has kindly resterised the image for you. When you zoom in, it's blurry, not as before.

[ygoe]

Here's the image I've tested it with right now:

This is what it looks like after adding it to the document, zoomed in for detail:

And this happens after rasterisation: (same zoom level)