From 00424555cf2d7be43204eb54b3dbee4b10c8a6dc Mon Sep 17 00:00:00 2001 From: Tony Cook Date: Mon, 7 Jan 2002 23:32:23 +0000 Subject: [PATCH] more gif docs --- lib/Imager/Files.pod | 84 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) diff --git a/lib/Imager/Files.pod b/lib/Imager/Files.pod index a50eca75..63efce2e 100644 --- a/lib/Imager/Files.pod +++ b/lib/Imager/Files.pod @@ -252,10 +252,92 @@ will be eliminated from its palette. This is set by default. =back -colors parameter on read. +When reading a GIF all of the sub-images are combined using the screen +size and image positions into one big image, producing an RGB image. +This may change in the future to produce a paletted image where possible. + +When you read a single GIF with C<<$img->read()>> you can supply a +reference to a scalar in the C parameter, if the image is read +the scalar will be filled with a reference to an anonymous array of +L objects, representing the palette of the image. This +will be the first palette found in the image. If you want the +palettes for each of the images in the file, use C and +use the C method on each image. + +GIF does not support the spatial resolution tags. + +GIF will set the following tags in each image when reading, but does +not use them when saving to GIF: + +=over + +=item gif_left + +the offset of the image from the left of the "screen" ("Image Left +Position") + +=item gif_top + +the offset of the image from the top of the "screen" ("Image Top Position") + +=item gif_interlace + +non-zero if the image was interlaced ("Interlace Flag") + +=item gif_screen_width + +=item gif_screen_height + +the size of the logical screen ("Logical Screen Width", +"Logical Screen Height") + +=item gif_local_map + +Non-zero if this image had a local color map. + +=item gif_background + +The index in the global colormap of the logical screen's background +color. This is only set if the current image uses the global +colormap. + +=item gif_trans_index + +The index of the color in the colormap used for transparency. If the +image has a transparency then it is returned as a 4 channel image with +the alpha set to zero in this palette entry. ("Transparent Color Index") + +=item gif_delay + +The delay until the next frame is displayed, in 1/100 of a second. +("Delay Time"). + +=item gif_user_input + +whether or not a user input is expected before continuing (view dependent) +("User Input Flag"). + +=item gif_disposal + +how the next frame is displayed ("Disposal Method") + +=item gif_loop + +the number of loops from the Netscape Loop extension. This may be zero. + +=item gif_comment + +the first block of the first gif comment before each image. + +=back + +Where applicable, the ("name") is the name of that field from the GIF89 +standard. =head2 TIFF (Tagged Image File Format) + + =head2 BMP (BitMaP) =head2 TGA (TarGA) -- 2.39.5