Animates a number of AVS x format image files stored in memory or on disk.
module AVSImagePlayer < src_file="ximg_ply.cxx",
build_dir="iac_proj/ximg_ply",
out_src_file="gen.cxx",
out_hdr_file="gen.hxx",
cxx_name="xImgPlay",
cxx_members="private:
friend void AVSImagePlayer_LoopFuncTmp(char *arg);
void LoopFunc(void);
int ReadImages(void);
int ReadImage(int image_no, int data_array_index,
char *module_name); ",
cxx_hdr_files="fld/Xfld.h"> {
ImagePlayerParams+read+write+req &ImagePlayerParams<NEportLevels={2,0}>;
int trigger_run<NEportLevels={2,0}>;
int trigger_stop<NEportLevels={2,0}>;
int+read+req data_array_size = 1;
Data_Array+write+nonotify+nosave Data_Array[data_array_size] {
veclen = 4;
id = 669;
values+byte;
null_value+byte;
min+byte;
max+byte;
min_vec+byte;
max_vec+byte;
};
int node_data_index => switch((ImagePlayerParams.access_mode + 1),
0,ImagePlayerParams.count);
Mesh_Unif+Node_Data+write+nonotify out<NEportLevels={0,2}> {
ndim = 2;
nspace = 2;
points => { {0,0}, {(dims[0] - 1),(dims[1] - 1)} };
nnode_data = 1;
&node_data => Data_Array[node_data_index];
};
GDM.DataObject DataObject {
in => out;
Obj<NEportLevels={0,3}>;
};
cxxmethod+req image_player_run( trigger_run+read+notify+req );
cxxmethod+req image_player_stop( trigger_stop+read+notify+req );
};
AVSImagePlayer is a low level module that is able to read in image files in the AVS x format and then animate them from either memory or by loading each image as it is required. The image filenames are specified by using a C-style format-string and a number of parameters. The module is also able to control the rate at which the images are animated, whether the animation runs forward or backwards and whether the animation cycles continously. The images are output as both a uniform mesh with colours represented by node data, and a renderable DataObject that is generated from the uniform mesh.
trigger_run
When updated this parameters triggers the start of the animation. The animation then runs until the trigger_stop parameter is updated, or until all images have been displayed if the animation is not cycling. When updated the parameter triggers the loading of image files into memory, should this be necessary.
trigger_stop
When updated this parameter halts the animation. The animation stops at the current frame. This parameter does not reset the animation to either the first or last frames.
&ImagePlayerParams
Reference to the parameter block, which contains real instances of the parameters for the AVSImagePlayer function.
ImagePlayerParams.file_format
Filename formatting string that specifies the filenames of the image files that are to be loaded. The parameter is of type string. This parameter uses a C-style formatting expression to generate indexed filenames.
Therefore setting file_format to "Imag%d.x" will generate filenames of the form "Image0.x" with no leading characters; whilst setting the parameter to "Image%04d.x" will generate filenames which are padded with zeros to be 8 characters long (i.e. "Imag0001.x"). More information can be found in any C reference book.
ImagePlayerParams.nb_images
Total number of images that are to be animated. This parameter is of type int. The animation will stop or repeat as appropriate when this many frames have been displayed.
ImagePlayerParams.first_image
Index number of first image to be animated. This parameter is of type int.
ImagePlayerParams.step
Value that the index number should be incremented by during each iteration of the animation loop. This parameter is of type int.
ImagePlayerParams.access_mode
Specifies whether images should be animated from memory or from disk. This parameter is of type int. Setting the parameter to 0 specifies that each image should be read from disk immediately before it is displayed. Setting the parameter to 1 specifies that all the images should be loaded into memory before the animation begins and displayed directly from memory.
ImagePlayerParams.run_mode
Specifies how the animation should be performed. This parameter is of type int. There are four possible values for this parameter:-
ImagePlayerParams.fps
Number of frames per second that the images should be animated at. This parameter is of type float. This is the ideal number of frames per second, if the system is unable to achieve this value then the animation will run at a lower rate.
ImagePlayerParams.nsec_before
Specifies the number of seconds that the animation should wait at the starting frame before the animation is restarted. This parameter only applies when the animation is cycling. The parameter is of type int.
ImagePlayerParams.nsec_after
Specifies the number of seconds that the animation should wait at the ending frame before the animation returns to the starting frame. This parameter only applies when the animation is cycling. The parameter is of type int.
ImagePlayerParams.count
The index number of the currently displayed image. This parameter is of type int. Setting this parameter will cause the currently displayed image to change immediately.
ImagePlayerParams.real_fps
Number of frames per second that the animation is actually running at. This parameter is of type string. The parameter is intended for display only and to ease display the number of frames per second is included along with an appropriate message by the module.
out
Field data containing the currently displayed image. The image is represented by a uniform mesh. The colour of each pixel is represented by a vector of length 4 (i.e. alpha, red, green, blue) at each node data point.
obj
The directly renderable output field of the AVSImagePlayer module. This contains a DataObject object that can be rendered by the standard data viewers. The DataObject is generated directly from the field data created from the currently displayed image.
The low-level AVSImagePlayer module is used in the User Macro imagePlayer. Additionally, this macro also uses the ImagePlayerParams parameter block group object, as does the ImagePlayerUI UI Macro.
An example application AVSImagePlayerEg is provided, which uses the animation module to display a sequence of images generated for a Meteorological Office presentation on global warming.
iac_proj/ximg_ply/iplymods.v contains the ImagePlayerParams group and the AVSImagePlayer module V definitions.
The low-level AVSImagePlayerMods library containing the module AVSImagePlayer does not specify a process. By default the express process will be used.
Fernand Alcatrao
Andrew Dodd
International AVS Centre Manchester Visualization Centre Manchester Computing University of Manchester Oxford Road Manchester United Kingdom M13 9PL
ImagePlayerParams, ImagePlayerUI, imagePlayer