Definitions / Jargon
First, a couple "definitions" that specifically apply to how we use certain terms in this article - this is NOT an exhaustive dictionary.
as used in this article, we mean an AtalaIamge object or more broadly a "RASTER" image which means an image object that is based on a "grid of pixels" as opposed to specific image formats (tiff, jpeg, etc)
as used in this article we're referring to a pdf but NOT as an image extracted or rasterized from a PDF
ImageSpace / Image Space / Image Coordinates
ImageSpace and these other terms will refer to how one navigates coordinates when working with an Image object
PdfSpace / PDF Space / PDF Coordinates
PdfSpace will refer to how one navigates coordinates when working with a PDF in one of our classes such as PdfDocument, PdfGeneratedDocument, PdfTextDocument, etc
A system.Drawing.Point object which is expressing an X, Y coordinate in ImageSpace
In Image space, a Point is integer value as a single point identifies a single pixel there is no such thing as a partial pixel in ImageSpace
A System.Drawing.PointF object which is expressing an X, Y coordinate in PdfSpace
Critically, a PdfPoint is 1/72 of an inch AND the PdfSpace coordinates are measured 0,0 is bottom left and as X increases you move right (same as ImageSpace) but eacn uniit is a 1/72 inch step, but as Y increases you go UP toward the TOP of the page (also segmented into 1/72 of an inch)
Images from PdfDecoder
When you use our PdfDecoder to make an AtalaImage ... the PdfDecoder RASTERIZES the image .. converting whatever the 100% VIEW of a specific page is into a grid of pixels with the PdfDecoder.Resolution (default is 96 which is quite low) is set to. Once you have an AtalaImage, the fact that it came from PDF doesn't matter.. it's now an Image and is living in "ImageSpace"