[Feature Request] Return image.Gray, when FPDF_RENDER_FLAG_GRAYSCALE is set

[jj10052]

I'm using RenderPageInDPI() with the flag FPDF_RENDER_FLAG_GRAYSCALE, because I need a gray scale image. The responses.RenderPageInDPI response returns an image.RGBA, which makes it necessary to convert to an image.Gray afterwards. This is a computationally intesive task.

Is it possible to return an image.Gray instead of an image.RGBA when FPDF_RENDER_FLAG_GRAYSCALE is set?

To me it seems like the main change is the creation of the image in renderPages. Here it needs to be image.NewGray(...) instead of image.NewRGBA(...).

[jerbob92]

Hi! It's sadly not that simple since the response struct expects an *image.RGBA, not image.Image, it does require a bit more work as well, but I think it can be done. Will look into it but it would probably require a new major version because of backwards incompatibility.