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I used GIMP to create images, but, since I needed to produce higher quality images, I recently switched to Inkscape. Now I have created a sample text with black background in it, and I am not able see any major difference from vector to pixel.

I zoomed the image and noticed that I could see the image pixels. Why is these happening? What is the major difference between these two (I have heard that vector images are higher quality than pixel because of the distortion that pixel type has, but I am not able to figure it out)?

Image sample:
Image sample

What would be an example of which type of image is high quality vector or pixel?

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I have tried to reword your post so that it makes a bit more sense to the readers. If you think my editing changes what you were trying to ask let me know in a comment below –  Shakehar Jul 23 '13 at 19:25
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4 Answers

up vote 5 down vote accepted

Pixel-based ("raster") formats break the image up into a limited number of points (pixels), where each pixel displays a given color. If the pixel density is high enough, our eyes won't be able to discriminate between the individual pixels, giving the appearance of a smooth image. However, as the density decreases (i.e. via zooming in), such that fewer pixels will be used to fill the same amount of space, the pixels will become more obvious (the image will appear "blocky"). Vector graphics, on the other hand, consist of specifications for paths through the image space (like, say, a line or a curve). Thus, you can choose any section of the image and any level of zoom, and the computer will re-compute and re-draw the paths. This allows the image to appear smooth no matter the zoom level.

The advantage of vector graphics is their persistent image quality. However, they have the disadvantage of being computationally heavy: zooming and panning an image requires a recomputation of the view of every path. Also, many graphical effects (blurring, distortion, etc) depend on a rasterized image since they work via pixel-based calculations. Also, vector graphics should require far less disk space than a high-resolution raster image. On the other hand, some types of images, such as photographs, are simply more practical in raster formats.

As for comparing text written in Gimp and Inkscape, I'm not 100% sure how Gimp works, but when you initially enter text in a text box, it might be vector-like. I bet if you first rasterize the image with the text (i.e. export it as a bmp) and then compare the bmp with the image in Inkscape, you'll see the difference.

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thanks for your time and answer. Here is the image created using inkscape, in this if you zoom you can able to see dots at the text borders and circle located at top with mild white colour i43.tinypic.com/vg3cw0.png –  raj Jul 17 '13 at 14:15
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The moment you save an image created in Inkskape as a PNG, you convert it from a vector image to a raster image. That's why you see the pixels. If you keep it as an SVG file, you will not have this problem. –  Brandon Invergo Jul 17 '13 at 14:22
    
so you are saying only .svg extension image alone has property of vector not any other extension(.jpg .png .gif) right? i thought if we create images using vector based software then we can export it to any type with the same quality. –  raj Jul 17 '13 at 14:36
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JPG, PNG and GIF are all raster image formats. It doesn't matter how you create them; once they're created, they consist of a set number of pixels and are thus subject to the quality restrictions of raster images. The best you can do is to export to as high of a resolution as possible, but remember that this will increase the resulting file size greatly. –  Brandon Invergo Jul 17 '13 at 14:38
    
Thanks.Can SVG only used for web or any other? –  raj Jul 18 '13 at 10:41
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A crap image is a crap image. Nothing can save a picture of Man-Faye.

It's probably useful to understand the actual difference between a raster image and a vector image. Nearly every digital image you see is the former - its many small dots forming a picture. To resize this, you at the minimum need to increase the number of dots forming the image, and this makes it look bad (there's better ways, but even then, you can only put that much lipstick on a pig).

A vector image on the other hand, is a set of rules telling a program how something needs to be drawn. For example, a box would be a set of instructions saying "From the origin point, draw a line 10 pixels long, turn 90 degrees right, and draw a second line 10 pixels long, turn 90 degrees right and..." This means all you need to do is to adjust these rules - say doubling all the lengths to get a bigger picture.

High resolution vector images are probably easier to work with. Vector images scale better to ANY size you need.

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thanks for the answer please note my comment in Brandon Invergo –  raj Jul 17 '13 at 14:19
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The key difference between raster (pixel data) graphics and vector graphics, is that raster graphics won't scale up because they contain data for each pixel on screen. Vector graphics are drawn using mathematical functions to define curves via points on screen (and hence can be interpolated to be scaled infinitely)

GIMP is a raster program with some vector support. That's to say, that when you set up a document, you define its pixel resolution. Therefore, it only renders vectors for those pixels defined by the document (so you are essentially looking at another raster image, hence quality degradation upon zooming) Photoshop does the same thing. Real vector applications don't have a "size" in pixels because it is irrelevant.

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thanks for your time please note my above comment –  raj Jul 17 '13 at 14:20
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The quality is the same, but if you zoom there's a difference. If you zoom in on vector graphics it will stay sharp; with pixel-graphics you will see the pixels!

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thanks for your time please take a look at my sample image given in above comment –  raj Jul 17 '13 at 14:22
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