From 454d0818e5ad0820771abebefa9758c66068b8d1 Mon Sep 17 00:00:00 2001 From: Travis CI Date: Thu, 19 Mar 2015 19:33:23 +0000 Subject: Gem 206d71791bc3642e8c5391a4c59c30ba7411fab8 osx/i386 built 'coverity_scan:206d71791bc3642e8c5391a4c59c30ba7411fab8' for osx/i386 --- Gem/manual/Pixes.html | 105 -------------------------------------------------- 1 file changed, 105 deletions(-) delete mode 100644 Gem/manual/Pixes.html (limited to 'Gem/manual/Pixes.html') diff --git a/Gem/manual/Pixes.html b/Gem/manual/Pixes.html deleted file mode 100644 index badf8bc..0000000 --- a/Gem/manual/Pixes.html +++ /dev/null @@ -1,105 +0,0 @@ - - - - - - - Pixes (image processing) - - - -
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-Image processing

-The pix objects are used to do image processing to pixel data. If -you load in an image with [pix_image], then you can change what the -image looks like before rendering it out -

In general, processing images is extremely expensive, so you -probably cannot have that many active pix objects. GEM only reprocesses -images when the source image changes or one of the parameters for a pix -object changes. This means that GEM will only process an image when -something is different, instead of every frame. If you want to do -a lot of processing at start up, but then not change anything once the -patch is running, GEM will only do the computation once.
-Modern CPUs use SIMD (Single Instruction - Multiple Data) (like MMX, SSE2, altivec) -to make pixel-processing more effective (by processing data parallely). -Until now, only the macOS version of Gem has support for SIMD for some pix-objects. -MMX/SSE2 boosts will hopefully come in future Gem-releases. - -

The pix objects are divided into two general groups, those which take -one input, and those which require two input images. For example, -[pix_invert] -will "invert" all of the pixels (if a pixel is white, it will change to -black), while [pix_add] will add two images together. -

Only some of the pix objects are described here. Look in the reference -patches for explanations for the other pix objects. -

[pix_invert] - invert the pixel data -
[pix_add] - add two pixes together -
[pix_mask] - create an alpha mask -
[pix_convolve] - convolve a pix with a kernel -

-

-[pix_invert]

-[pix_invert] inverts the pixels in an image. To use [pix_invert], -simply make sure that you have already loaded an image into the chain. -In the following patch, the fractal image will be inverted. -
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Here is the difference between the fractal image and the inverted version. -

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-pix_add

-[pix_add] does what you would expect. It adds two images together. -
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This patch adds the fractal image with a car image. The processed -image will often contain a lot of white pixels, because the data is just -added together. This occurs in the resulting image, shown below. -

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-pix_mask

-[pix_mask] is used to create an alpha mask from another image. -In the following example (gem_pix/gemMaskDancer.pd), the fractal image's -alpha channel is replaced by the dancer image. If the [alpha] -object was removed, then you would just see the solid fractal image (because -the alpha channel wouldn't be used). -

In other words, images are composed of a red, a green, a blue, and an -alpha channel. The alpha channel is the transparency of the pixel. - -[pix_mask] only modifies the alpha channel and does not touch the -red, green, or blue data. -

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The result is this image. -

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-pix_convolve

-[pix_convolve] convolves pix data with a convolution kernel. -Basically, you can get really nice effects if you choose the correct kernel...and -garbage if you choose the wrong one. -

Edge detection is done with a convolution kernel, as is smoothing. -The biggest problem is that convolving an image is about the most expensive -operation that you can do in GEM. -

Look at gem_pix/gemPixConvolve.pd to get an idea of some of the kernels -that you can send to [pix_convolve] and the effects that you can get. -

If you want to learn the math behind convolution, then find any standard -image processing (or audio processing book, this is just 2D convolution). -
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[return] -
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