Warning, /graphics/digikam/core/dplugins/generic/view/glviewer/README is written in an unsupported language. File is not indexed.
0001 -------------------------- 0002 OpenGL image viewer plugin 0003 -------------------------- 0004 0005 This image viewer was designed with speed and ease of usage in mind as well as for mouseless setups (notebooks). 0006 A image is converted to a non-power-of two OpenGL texture. This means your video driver has to support the GL_ARB_texture_rectangle 0007 OpenGL extension. Please verify with the command glxinfo. 0008 0009 Please keep in mind that you need a lot of video memory: a 5MP image requires 20MB texture memory. 0010 If you run out texture ram, the downloading time of the texture can be increased up to several seconds. 0011 0012 ------------------- 0013 Handbook 0014 ------------------- 0015 0016 1) Start 0017 -------- 0018 0019 - select the images you'd like to view. Ctrl-A for all images 0020 if no image is selected, all images of the album are loaded and the first image will be displayed 0021 if one image is selected, all images are loaded and the selected image image will be displayed 0022 if several images are selected, only the selected images are loaded 0023 - select View->OpenGl Image viewer 0024 - for convenience, create a shortcut in the host application. In digiKam, select Settings->Configure Shortcut, search for "image viewer" 0025 0026 0027 2) Usage 0028 -------- 0029 0030 next image : scrollwheel down or n or down arrow or right arrow or Space 0031 previous image : scrollwheel up or p or up arrow or left arrow 0032 toggle fullscreen/normal : f 0033 quit : Esc 0034 toggle scrollwheel action : c (scrollwheel either zooms or changes the image), default is changing images 0035 rotation : r 0036 reset view : double click 0037 original size : o 0038 0039 0040 zooming: 0041 0042 - move mouse in y-direction while pressing the right mouse button 0043 - alternatively, press c and use the scrollwheel 0044 - plus/minus 0045 - ctrl + scrollwheel 0046 0047 0048 panning: 0049 0050 - move mouse while pressing the left button 0051 0052 0053 3) Performance & technical details 0054 ---------------------------------- 0055 0056 On a PentiumM 1Ghz, slow 2.5 inch harddrive, I measured the following times for changing an image (5 megapixel, 2MB) 0057 - loading image from cache: 0ms 0058 - download texture to video memory: 15ms 0059 - draw image: 16ms 0060 the new image is on the screen after 31ms of the user interaction 0061 - preload next image to cache 690ms 0062 only after preloading is done, the next image can be displayed. 0063 0064 The most expensive part is instantiating a QImage(myimage) object with 690ms, 0065 which includes reading the file from the harddrive. 0066 Downscaling to screensize and converting to GL format takes around 70ms. 0067 At least on my setup, downscaling by CPU is still faster than copying a 20Mb texture to video mem and downscaling by GPU. 0068 0069 Other programs/libraries: time of loading and displaying an image 0070 SDL: 750ms 0071 Kuickshow: (imlib) 690ms (without smooth rendering) 0072 Kuickshow: (imlib) 1770ms (with smooth rendering) 0073 feh: (imlib2) 670ms 0074 this Image Viewer plugin: 720ms (implicit smooth rendering due to OGL)