Display Options

The display options control the look, performance and display of images. To open the display options dialog, press 'd' (default hotkey).

When done setting the options, select 'Apply' (to apply and keep the window open) or 'Accept' (to apply and close the window).  If "Save as Default" is selected, the display options are saved in $HOME/houdini[Version]/mplay.prefs for future sessions.

Display Page

Integer Image Scaling Only
If enabled, zooming will scale or shrink the images only by integer amounts (2, 3, 4, 1/2, 1/3, etc).

Auto Mipmap Images
If enabled, mipmaps are generated on demand when the image is zoomed out beyond 3x. This may produce a slight delay during scaling as the mipmap is generated.

Pop window when rendering Images
When rendering images, this option will pop mPlay to the front of the window stack whenever a render is started.

Fast Pixel Aspect Ratio Display
For pixel aspect ratios other than 1:1, this enables a fast, hardware horizontal scale to produce an image that appears to be at the correct aspect ratio. However, this can produce scaling artifacts. If off, a slower, software horizontal scale is used that eliminates these artifacts.

Video Card Options...

This pops up a dialog for troubleshooting video card problems. There are 3 high level controls, which will set the individual options:

Use Color Dithering
Dithers the images to approximate the image's full colour depth (when the display is not capable of showing the image's full colour depth). Dithering places adjacent pixels close to the actual colour next to each other in order to make it appear like the real colour - from a distance, the resulting "speckled" pattern appears to resemble the actual colour. Dithering also helps break-up moiré patterns if they exist.

Display Images at 8bit Pixel Depth
If enabled, all images are compressed to an 8 bit pixel depth. Otherwise they are passed to OpenGL in their native format (floating point, 16 bit or 32bit).

Use Hardware Accelerated Colour Functions
If your graphics card supports OpenGL hardware acceleration, enabling this option will use that capability to speed-up colour calculations. OpenGL colour functions affect the gamma, brightness, contrast and other functions.
Only disable this if your video card does not implement these functions properly, in which case, images will either not appear or the colour functions will have no effect.

Use Hardware Accelerated Lookup Tables
Attempts to use hardware OpenGL features when the Gamma is set to a value other than 1, or a lookup table is applied to the image (using the -l command line option (mplay) or the Viewport Display LUT in the Display Options). If playback is much slower, or the LUT has no effect, turn this option off.

Use Luminance Images for Single Frames
Uses a single monochrome 8 bit image to display 1 channel images such as Alpha, Masks and Z-Depth. Turn this option off if these types of images do not display, or if display of these images is substantially slower than normal colour images. These images will be promoted  to greyscale RGB for better performance (but consuming three times the memory).

RGB Component Display Mode
Sets the Component Selection Hardware mode viewing R, G, and B, individually. Hardware greyscale shows R, G and B as greyscale images. Hardware RGB shows R as red, G as green, and B as blue. Software greyscale shows R, G and B as greyscale, but does the conversion in software (some video cards cannot do this efficiently in hardware - long delays in panning or noticable colour flickering are symptoms).

Viewport Page

This page has options for viewport layout and display.

Multiple Node Display
Specify a Split View or a Single View to be used for displaying multiple nodes.

Layout Horizontally First, then Vertically
If enabled, images are added to Viewports with a horizontal preference.
If disabled, Viewports are added verically first. This only applies when more than one row and column are used in the viewport layout (ie 2x2, 4x2, 3x3).

Show All Viewports Always
If enabled, all the viewports specified by the layout will be visible, even if whole rows or columns of viewports are empty. If off, the viewer dynamically adapts the number of viewports up to the layout specified.

Default Viewport Layout
Specifies the default startup layout of the viewports, from 1x1 to 4x4.

Display Viewport Information
Specifies the amount of information present in the viewport information labels, from Minimal (name only) to Verbose (all image information displayed).

Image Guide
The name of an image guide file. The guide file is a text file with a series of drawing commands which will overlay a guide on the image. All coordinates are expressed in pixels.

Image Guide Commands
box X Y Width Height
Draws a box at (X,Y) with the specified width and height.
rect X1 Y1 X2 Y2  
Draws a box with one corner at (X1, Y1) and the opposite corner at (X2, Y2).
line X1 Y1 X2 Y2  
Draws a line from (X1, Y1) to (X2, Y2).
lines Num dX dY X1 Y1 X2 Y2  
Draws a series of lines from (X1, Y1) to (X2, Y2), offseting both coordinate pairs by (dX, dY) each time. Num lines are drawn.
color R G B A
Sets the drawing colour to {R,G,B,A}.


Background Colour
Specifies the background colour of the image viewer, normally black. Click the colour preview to display a colour picker dialog.

Background Page

Background images will always be stretched to fit the size of the currently displayed image. If the aspect ratio of the background image and the current image do not match, you will get distortion of the background image.

Note: Background images are only visible when Transparency is enabled.

Filename
The name of the background image to use. If none is specified, then no background image will be displayed.

Use Res
Manually specify a resolution to use for the background image instead of using the natural size of the image.

Foreground Images are Premultiplied
Most rendered images are premultiplied, which means that the colour has already been multipled by the alpha plane. However, if just place an arbitrary alpha plane without running it through a Premultiply COP, then the resulting image is not premultiplied, and your transparency will be wrong.

For example: Place a File COP, append a Shape COP and have it replace the Alpha plane with a star shape,  then enable transparency. You'll need to turn off "Foreground Images are Premultiplied" in order to see the proper image.

Correction Page

This page contains options for color correction of the displayed images.

Display LUT
Applies a LUT file to the display images.

Inspect LUT
When inspecting, the raw values of the image will be run backwards through the LUT file to produce the original values (i.e. Cineon values).

Default Display Gamma
The default gamma applied to all images, which can be interactively changed using the color correction controls.

Gamma Correct Planes
The names of planes to gamma correct. Normally, this is just the colour plane (C).

Handles Page

This page contains options for the display of handles and guides.

Render with Smooth Lines
If enabled, the handle and guide lines will be anti-aliased.

Render with Alpha Blending
If enabled, the handle and guide lines will be slightly transparent.

Handle Colour
The basic colour of all handles and guides. The default is bright grey. Specify an rgb for the handle colour, or click the colour preview to display a color picker.

Handle Pick Size
The size of the handle's pick region (in pixels). Larger values make the handles easier to pick, however, values above 10 should be used with caution, since handles may be unintentionally picked with such a forgiving value. This option does not have an effect in mplay.

2.6  Memory Page

This page contains options for memory usage.

Limit Viewer Memory Usage
If enabled, the image cache has a maximum size specified by the Image Cache Size.

Image Cache Size
The size of the image cache, in Mb.

Image Compression
If memory is short, you may want to apply lossless compression to images. This enables lossless compression on the cached images, with varying degrees of compression/CPU usage.

Clear Images from Memory
Flushes the image cache, freeing all image memory, exception that used by the currently displayed image(s).