Images

From bdae26678d39c83280ed5e353986705da6f423c5 Mon Sep 17 00:00:00 2001 From: Travis CI Date: Thu, 19 Mar 2015 23:06:26 +0000 Subject: Gem 4990e2aec04f67a68fbd2878f4d99bb8042f68fa osx/x86_64 built 'master:4990e2aec04f67a68fbd2878f4d99bb8042f68fa' for osx/x86_64 --- Gem/manual/Images.html | 112 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 Gem/manual/Images.html (limited to 'Gem/manual/Images.html') diff --git a/Gem/manual/Images.html b/Gem/manual/Images.html new file mode 100644 index 0000000..182d153 --- /dev/null +++ b/Gem/manual/Images.html @@ -0,0 +1,112 @@ + + + + + + + Images + + + + +

+Dealing with Images

+Images are files which are loaded into GEM. The images can be manipulated, +applied to objects, and used in any number of different ways. In +this section, you will load in an image and display it on the screen. +This section will not apply the images to a geo; that occurs in +the next part of the manual. +

The pix objects are GEM objects which deal with pixels. +They do everything from loading in images to applying filters to the data. +The objects in this section of the manual only load in pix data from outside +sources. How you actually display the image is up to you. The +most common usages are with [pix_draw] and [pix_texture]. +

Warning: [pix_draw] is almost always slower than [pix_texture]. +Because [pix_draw] is easier to use than [pix_texture], it is +used in these examples. However, in any real usage or piece, [pix_texture] +should always be used instead. [pix_draw] is slow because PC +graphics accelerators do not provide hardware acceleration for that functionality. +[pix_texture] does have hardware acceleration and will be much faster. +

[pix_image] - load in an image +
[pix_multiimage] - load in multiple images +
[pix_movie] - load in a movie file +
[pix_video] - use a real time video source +

+[pix_image]

+[pix_image] is used to load in images. Images can be in a variety +of different formats, including TIFF, JPEG, and SGI formats. The +patch gem_pix/gemImage.pd is the simplest use of the [pix_image] object. +In this patch, the [pix_image] object loads in the file dancer.JPG. + +

+ +

As is the case with every GEM chain, this patch starts with the [gemhead] +object. The next object is [pix_image], which actually loads +the image. [pix_image] makes the file dancer.JPG the current +pixel data, which will be used in all subsequent operations in the chain. +The [translateXYZ] object is used to move the image around. +Finally, the [pix_draw] object renders the pixel data to the screen. +

The patch mentions that changing the Z in [translateXYZ] does not +change the size of the image, as would occur with a geo object like +[square]. +This is because [pix_draw] simply draws the pixel at the current raster +position, without any transformation. If you want to change the size +on the fly and rotate the image, you need to texture map the pix, which +is described in the next section. +

+[pix_multiimage]

+The [pix_image] object only loads in one image at time. If you +try to change the image rapidly while the patch is running, you will notice +a lag every time it has to load in a new file. To avoid this lag, +there is another object called [pix_multiimage]. If you look +at patch gem_pix/gemMultiImage.pd, you will see this object in action. +

Basically, the * in the file name is replaced by the number that you +pass in. This allows you to play sequences of images with random +access. The one downside is that every image is loaded into memory +when the object is created, so you need to have a lot of RAM to use it. +

[pix_movie]/[pix_film]

+These objects are used to read movie-files from disk (or if supported from the internet). + +The movie is streamed off of disk, +using whatever decompression libraries are installed on your computer. +On Windows AVI movies seem to work fine, +but there is also a prelaminary support for quicktimes (and mpeg). +On macOS-X all formats supported by the system (basically: quicktime) should work ok. +On linux the support is highly depending on what libraries are installed during compile time. +There is support for MPEG (with libmpeg1 or (preferred:) libmpeg3), +quicktime (either libquicktime or quicktime4linux; +most likely you will not be able to decode quicktimes with proprietary codecs) +and AVI (with libavifile which is able to utilize windows-dlls for (proprietary) codecs). +There is also some rudimentary support for FFMPEG. + +The right inlet of [pix_movie] +accepts a number to specify the frame to display. Look at 04.pix/04.movie.pd +for an image. +

A key fact of [pix_movie] is that it immediately sends the movie +data to OpenGL as a texture map. This means that you do not need +the [pix_texture] object in your chain. This also means that +you cannot process the movie data with pix objects. The main reason +for this is that it removes the need for a copy of all of the movie data. +If you want to apply some image-processing, you will have to use [pix_film] +(and [pix_texture] for texture-mapping). +

Some of the geos will not texture map the [pix_movie] data correctly. +Cone and sphere do not use texture coordinates when they are provided, +so when you display a movie on one of these objects, you will have a black +region (unless your movie size is a power of two...however, most movies +are 320x160 pixels or something). This will be fixed in a future +release. +

+pix_video

+The "image" can come from the [pix_video] object. +This means that you can use a real-time video source and display it on the screen. +

You can play with [pix_video] with the patches in 04.video/. +The patches are explained in more depth in the advanced section of the GEM manual. +

[return] +
+ + -- cgit v1.2.1