Why? Because auto-tracing features (at the current state in mainstream drawing programs) don't know what a 3-year old does: that a puppy's pupils are round. A manually traced puppy pupil will be round, have no more than four nodes, and will appear just as round and smooth when enlarged to the size of the moon. If you want a truly scaleable vector-based drawing of an image, you manually trace the raster image, using human discernment, and skill and understanding in drawing paths with economic efficiency.Ī puppy pupil auto-traced with high "accuracy" settings may be a tiny irregular shape with a dozen nodes, that looks just awful when enlarged beyond the size of a speck. And that defeats the whole resolution-independence advantage, reason, and intent of vector-based graphics. In other words, effectively, there would be no difference, and zooming into or scaling the now all-vector result would be no improvement whatsoever.Īuto-tracing quite often just trades vector jaggedness for raster jaggedness. Now ask yourself: At the most technically accurate settings, what would you get? You would get one perfectly square vector path for each pixel in the raster image. So you try the whole thing again, but trying supposedly "more accurate" tolerance settings. It's just a different "style" of jaggedness. There is no increase in detail, so zooming into the vector-based result is just as ugly and "jagged" as was zooming into the raster image. You zoom into it and find that the pupils are not a bunch of square pixels, but now a fewer number of jagged irregular shapes. So based on those two commonly-heard assertions (gross oversimplifications), you assume that auto-tracing will give you a graphic that can be zoomed or scaled to any amount and always look "smooth." You've heard people say that "vector graphics are resolution-independent" and that you can zoom into them forever without their becoming "jagged." You've heard that programs can automatically "convert" a raster image into a vector graphic. The puppy's pupils, for example, don't even appear round. But the resolution of the photo is so low that when you view it at 400% zoom, it looks pixelated. Auto-tracing does not add any detail that will suddenly make an image look "smooth" when zoomed in. You don't get something for nothing with auto-tracing. Think of it as the vector version of the "jaggies." Vector graphics can easily be just as jagged (and just as ugly) as pixels.Īnd that is very often the case with the results of auto-tracing because it is done by an automatic algorithm completely devoid of human shape recognition or knowledge of what is considered "smooth." It is quite common that if you zoom into the entirely vector-based results of auto-tracing, you see a jumble of jagged, irregular paths. That is not the only kind of ugly jaggedness that occurs in computer graphics. Pixelation results from scaling (or zooming) a raster image sufficiently large that the square shape of the individual pixels that comprise the image become evident. But "smooth" and "non-pixelated" are not the same thing.
#Mac convert raster to vector pdf#
If you zoom into a raster image in a PDF (or in any other file), yes, you should expect to see pixelation. If you want to understand what you're hoping to do, read on:
The details are all in the documentation. Perform the auto-trace, using the settings that yield results most acceptable to you.Create an Illustrator file (or open an existing one).How do I do this in Ai or id there a better Adobe program Then you would do the auto-tracing in a file that is set to RGB color mode.
It has nothing to do with the file being a PDF. It is only the raster objects (images) which will appear pixelated when you zoom in.
If I open the new PDF file and open to 4))% I expect smooth non pixelated lines If I open to original PDF file and zoom to 400% I expect pixelated lines Putting the result of auto-tracing in a PDF file is like doing so with any other kind of content: Just a matter of saving the file as a PDF. It can contain any combination of raster, vector, or text objects. There is no such "conversion." There is only re-drawing the content of the raster image.Ī PDF is just a container. in Illustrator, depending on version).īut you must understand: Auto-tracing is not a lossless 1:1 "conversion" in the sense of "converting" between units of measure or "translating" between file formats. You're probably talking about auto-tracing (called Live Trace or Image Trace, etc. I want to convert that Raster Image to Vector I have an image in a PDF file that is a Raster Image
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