![]() That means only the three color channels of the image were blurred, leaving ![]() Operator, is limited by the " -channel" setting, to just the three colour channels. Well in actual fact the operator did work. Hang on, what happened! The image didn't change! fill black -draw 'circle 35,35 20,25' black_circle.pngĬonvert black_circle.png -blur 0x8 black_blurred.png It justīut if we try this again with an image containing a transparent background. fill black -draw 'circle 35,35 20,25' circle_on_blue.pngĬonvert circle_on_blue.png -blur 0x8 circle_on_blue_blur.pngĪs you can see a blurring a plain image like this has no problems. To demonstrate blur, lets start simply by generating a fuzzy black circle on a This way for a very long time, and would break too many things. This is unlikely to change as it has been As such a single value argument to these type Value, so it should be radius that is optional, as radius can beĪutomatically determined. Highlighting effects (as shown thought the Advancedĭue to the way IM handles ' x' style of arguments, the Shadow effects (see Compound Fonts), or even image Large values however are useful for producing fuzzy images, for backgrounds or I find a blur of ' 1x0.3' an useful value to remove most of the ![]() Smooth edges on images for which no anti-aliasing was used (see Anti-Aliasing for more info). Small values for the sigma are typically only used to fuzz lines and When possible use a radius of zero for blurring operations Smooth Gaussian curve of the blur, and thus producing Ringing Artefacts along sharp edges. Neighbourhood 'cutting off' the area blurred, producing sudden stops in the Sigma of ' 65355' will produce a simple averaging of allĪlso notice that for smallish radius but a large sigma you seeĪrtifacts appear in the blurred result. Limits their contribution to a small amount, while a larger sigmaĬontributes more equal amounts from all the neighbours. How much each neighbour contributes to the final result is still controlled by The nearest integer, to determine the 'neighbourhood' of the blur. If aįloating point value is given (or internally calculated) it is rounded up to Note that while sigma is a floating point, radius is not. Very small radius such as ' 1' effectively limited theīlurring to within the immediate neighbours of each pixel. That many pixels of the one being blurred (a square radius). bordercolor white -border 20x10 blur_source.pngĪ small radius limits any effect of the blur to pixels that are within I also purposely used aįont that contains both thick and thin lines see the fuzzing of small lineĬonvert -font Gecko -pointsize 48 label:A \ Table of the results for various operator settings. Of surrounding space (blur operators need lots of room to work), and create a To show you the effects of the options lets take this simple image, with a lot Typically be either ' 0' or at a minimum double that of the The first value radius, is also important as it controls how big anĪrea the operator should look at when spreading pixels. The numbers are floating point values, so you can use a very Think of it as the size of the brush used toīlur the image. It canīe thought of as an approximation of just how much your want the image to The important setting in the above is the second sigma value. Processing, the argument values can be confusing. (See Blur vs the Gaussian Blur Operator.) Blur/Gaussian ArgumentsĪnd " -gaussian-blur" are the same, but to someone new to image The two as very close, but as " -blur" is a faster algorithm, it is generally preferred to theįormer even though the former is more mathematically correct. Their are two general image blurring operators in ImageMagick. To within the boundaries of a single pixel of the original image. It isĪlso very useful for smoothing the effects of the 'jaggies' to anti-alias the edges of images, and to round outįeatures to produce highlighting effects.īlurring is so important it is an integral part of Image Resizing, though a different method of blurring, which is restricted ![]() In this section we will look at both.īlurring images so they become fuzzy may not seem like an useful operation, butĪctually is very useful for generating background effects and shadows. Motion Blur Feathering Shapes using Blur (under construction)īlurring, and its opposite, sharpening of images is a very important aspect of.Large Blurs using resize Sharpening Images (Under Construction).Index ImageMagick Examples Preface and Index Blurring Images
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