pymel.core.windows.headsUpDisplay

headsUpDisplay(*args, **kwargs)

This command creates a Heads-up Display (HUD) object which is placed in a 2D inactive overlay plane on the 3D viewport. It is to be used to provide hands-on information designated by a user script. The text string displayed on the viewport is formatted using the various flags of this command. The only mandatory flags, on creation are the section and block flags. Note if the preset OR command/trigger flags are not present, only a label will be drawn on the viewport. Upon creation of a HUD object, an ID number will be assigned to it. This can be used to remove the HUD object (-rid/removeID [int IDNumber]), if desired. Alternatively, HUD objects may be removed via their position (section and block), or their unique name.

Flags:

Long name (short name)		Argument Types	Properties
allDescendants (ad)		bool
	This flag can only be used in conjunction with the -ac/attributeChange flag. If it is specified, and the HUD is attached to a compound or multi attribute, then the HUD command will run due to changes to the specified attribute as well as changes to its descendants.
allowOverlap (ao)		bool
	Sets the Heads-Up Display to be visible regardless of overlapping section widths/limitations (see -s/section flag description for more details).
attachToRefresh (atr)		bool
	Attaches the command to the refresh process. The script is then run each time an idle refresh is run and updates directly following it.
attributeChange (ac)		unicode
	Runs the command when the named attribute changes value. The string must identify both the dependency node and the particular attribute. If the dependency node is deleted, this HUD is removed (even if the deletion is undoable).
block (b)		int
	Denotes the individual block that the HUD will reside in, within a section. Each section is composed of a single column of blocks. The total number of blocks contained within each section is variable. The number of blocks that will be visible within each section is dependent on the size of blocks contained in each section and the current size of the window. Blocks begin enumerating from 0 and flexibly increase based on need. The resultant output string of each HUD is formatted within each block, using parameters defined by the formatting flags listed below (eg. justify, padding, labelWidth and dataWidth). The layout is shown in the following diagram: __________________________________________ | | | | | | | | P | J | LW | DWX | J | P | |_____|_____|________|_________|_____|_____| P = Sub-block of width, padding J = Justification of the entire block LW = Sub-block of width, labelWidth DWX = X number of sub-blocks of width, dataWidth, for X data elements. Block LayoutThe above diagram shows the layout of each block. The widths: padding, labelWidth and dataWidth are defined by their respective flags. To elaborate on the layout of the blocks, First the padding of the block is calculated. Then the two main sub- blocks (LW and DWX) in the above diagram, are justified and positioned together between the left and right margins of the block. The widths of the main sub-blocks are not variable based on it’s contents. The only sub-block in the above diagram which is unique is the DWX sub-block which actually represents X number of sub- blocks, where X is the number of data elements returned by the command. Block PositioningBlocks on the top section begin from the top edge of the main viewport, while the bottom section begins from the bottom edge. Blocks are dynamically removed from visibility from the midpoint of the viewport. So, a relatively large block number will not draw to the viewport. Lastly, there can be at most one HUD occupying a block at any time. Trying to position a HUD in an occupied block will result in an error. Keep this in mind when positioning the HUD.
blockAlignment (ba)		unicode
	Specifies the alignment of the block within its respective column. Available alignments are: “center”, “left” and “right”. The default alignment is “left”.
blockSize (bs)		unicode
	Sets the height of each block. Available heights are: small, medium and large. In pixel measurements, each corresponds to a 20, 35 or 50 pixel height, respectively.
command (c)		script
	Specifies the procedure or script to run, in order to obtain the desired information. This must return a value or an array of values. A warning will be displayed if the command does not return a value. This flag MUST always be accompanied by a trigger flag (eg. a condition flag, an event flag, an attachToRefresh flag, etc.).
conditionChange (cc)		unicode
	A trigger which runs the command (to sample the data), when the named condition changes. The named condition must be pre-defined or a user defined boolean. To get a list of what conditions exist, use the -lc/listConditions flag.
conditionFalse (cf)		unicode
	A trigger which runs the command (to sample the data), when the named condition becomes false. The named condition must be pre-defined or a user defined boolean. To get a list of what conditions exist, use the -lc/listConditions flag.
conditionTrue (ct)		unicode
	A trigger which runs the command (to sample the data), when the named condition becomes true. The named condition must be pre-defined or a user defined boolean. To get a list of what conditions exist, use the -lc/listConditions flag.
connectionChange (con)		unicode
	Runs the command when the named attribute changes its connectivity. The string must identify both the dependency node and the particular attribute. If the dependency node is deleted, this HUD is removed (even if the deletion is undoable).
dataAlignment (da)		unicode
	Specifies the alignment of the data blocks and the data text, within a HUD block. Available alignments are: “left” and “right”. The default alignment is “left”.
dataFontSize (dfs)		unicode
	Sets the font size of the returned data. Available sizes are: small and large.
dataWidth (dw)		int
	Specifies the pixel width of the virtual “textbox” which will hold a data value. For commands which return more than one value (ie. arrays), one of these “textboxes” will be created for each data element, each with this specified width. If the width of the data value exceeds the width of the “textbox”, the data value will be truncated to fit within the dimensions of the “textbox.” (To see a layout of a block, see the description of the -block flag.)
decimalPrecision (dp)		int
	Sets the decimal precision of any floating point value returned by the command. The valid range of precision values are 1 to 8.
disregardIndex (di)		bool
	This flag can only be used in conjunction with the -ac/attributeChange flag. If it is specified, and the HUD is attached to a multi (indexed) attribute, then the HUD command will run no matter which attribute in the multi changes.
event (ev)		unicode
	Runs the command when the named event occurs. The named event, must be a pre-defined Maya event. To get a list of what events exist, use the -le/listEvents flag.
exists (ex)		bool
	This flag returns whether the given object exists in the Heads-Up Display layout. An object name must be supplied with this command. This flag cannot be combined with any other flag.
getOption (op)		unicode
	This flag will return the value of the option specified by the string. See setOption for a list of options Flag can appear in Create mode of commandFlag can have multiple arguments, passed either as a tuple or a list.
gridColor (gco)		int
	This flag specifies a color for the grid lines using the inactive color palette. Specifying an index number between 1 to 23 will select the corresponding color in the palette.
label (l)		unicode
	Text string that appears to the left of the desired information.
labelFontSize (lfs)		unicode
	Sets the font size of the label. Available sizes are: small and large.
labelWidth (lw)		int
	Specifies the pixel width of the virtual “textbox” which will hold the label. The contents of this “textbox” will be left justified. If the width of the actual label exceeds the width of the “textbox,” the label will be truncated to fit within the dimensions of the “textbox.” (To see a layout of a block, see the description of the -block flag.)
lastOccupiedBlock (lob)		int
	Returns the block number of the last occupied block in a given section.
layoutVisibility (lv)		bool
	Sets the visibility of Heads-Up Display layout on and off. This does not modify individual visibilities of heads-up displays, but turns off the layout so that no heads-up displays will draw to screen. Personalized settings for the visibilities of HUDs are kept safe. This flag can only be used by itself, excepting edit and query.
listConditions (lc)		bool
	This flag will return a string array containing all names of the available conditions.
listEvents (le)		bool
	This flag will return a string array containing all names of the available events.
listHeadsUpDisplays (lh)		bool
	This flag will return a string array containing all names of existing HUDs.
listNodeChanges (lnc)		bool
	This flag will return a string array containing all names of the available node changes.
listPresets (lp)		bool
	This flag will return a string array containing all names of the available preset HUDs.
name (n)		unicode
	This flag only permits the EDITING of the name of the Heads-Up Display.
nextFreeBlock (nfb)		int
	Returns the block number of the next free block in a given section.
nodeChanges (nc)		unicode
	Works only with selection based triggers (ie. “SelectionChanged” or “SomethingSelected”), otherwise this flag is ignored. This flag attaches the HUD script to execute on specific node changes of any selected node. This flag is used to set a nodeChange. In order to reset a nodeChange, use the -rnc/resetNodeChanges flag. To view a list of all available node changes, use the -lnc/listNodeChanges flag. The following is a list of available node changes and their function: attributeChange: The script will be sensitive to any attribute changes in the currently selected nodes. connectionChange: The script will be sensitive to any connection changes in the currently selected nodes. instanceChange: The script will be sensitive to any changes to an instance in the currently selected nodes. On query mode, this flag will return the values of all nodeChanges in pairs of values (the name of the nodeChange followed by its value). WARNING: (Performance Warning) Attaching a nodeChange trigger to a selection based trigger can cause a large performance drop, if the node change that is being watched is caused by the HUD script itself. With this said, an attempt should be made to keep the HUD command/script simple and limited to retrieving data. Changing an attribute, creating or modifying a connection or instance will all result in a performance drop.
padding (p)		int
	Specifies the width of both the left and right margins of a block. Default value is 15 pixels.
preset (pre)		unicode
	This setting is used to select certain pre-defined HUDs, some of which retrieve specific data, that is unobtainable through normal MEL commands or scripts. This flag is mutually exclusive from the command and trigger flag combination. However, presets can work with all other headsUpDisplay attribute flags (ie. block alignment, label, dataFontSize, etc.), unless otherwise specified below. To obtain a list of available presets, use the -lp/listPresets flag on this command. The following is a list of available presets and a description of each: cameraNamesThis will return the camera name that the view is looking through, in the data block, for each view that the HUD is drawing to.polyVertsThis will return three values in the data block, regarding the number of vertices that are visible by the camera. 1st Value: Represents the number of camera visible vertices, both active and inactive.2nd Value: Represents the number of camera visible vertices, on active objects only.3rd Value: Represents the number of camera visible vertices, that are active.polyEdgesThis will return three values in the data block, regarding the number of edges that are visible by the camera. The order of these three values are similar to the polyVerts preset.polyFacesThis will return three values in the data block, regarding the number of faces that are visible by the camera. The order of these three values are similar to the polyVerts preset.polyUVsThis will return three values in the data block, regarding the number of UVs that are visible by the camera. The order of these three values are similar to the polyVerts preset.polyTrianglesThis will return three values in the data block, regarding the number of triangles that are visible by the camera. The order of these three values are similar to the polyVerts preset.frameRateThis will return a single string carrying both the frame rate and the “fps” string in the data block. It updates on each refresh.viewAxisThis will draw the orientation of the grid axes within the HUD. It updates on each refresh. While this preset can take in all attribute flags, the only one which will have an effect are block attribute related flags (ie. block alignment and block size). The block dimensions of this preset are: blockSize - “large” and blockWidth - “50”, which results in a 50x50 pixel region.distanceFromCameraThis will return in the data block the distance from the view’s camera to the centre of the bounding box containing the selected objects in the view.
refresh (r)		bool
	This flag forces the given Heads-Up Display element to refresh, updating the value displayed. This flag cannot be combined with any other flag.
remove (rem)		bool
	This command will remove a given HUD object, given a specified HUD name. This flag will override all other flags and is mutually exclusive from the other remove flags.
removeID (rid)		int
	This command will remove a given HUD object, given a specified HUD ID number assigned to it at creation time. This flag will override all other flags and is mutually exclusive from the other remove flags.
removePosition (rp)		int, int
	This command will remove the contents of a specific block location in the HUD layout. This flag will override all other flags and is mutually exclusive from the other remove flags. Syntax for this flag is: -removePosition/rp [section] [block].
resetNodeChanges (rnc)		unicode
	This flag will reset a specificied nodeChange back to false. This flag only operates under the edit flag. See the description for the -nc/nodeChanges flag for further details.
scriptResult (sr)		bool
	This flag is only used in conjunction with the query flag. Calling a query on this flag returns the most recent result of the HUD.
section (s)		int
	Defines the section the HUD will appear in. There are 10 sections divided across the screen. Five columns and two rows make up the ten element matrix which divide the main viewport. Here is a visual layout of the sections. ________________________ | | | | | | | | | | | | | 0 | 1 | 2 | 3 | 4 | | | | | | | |____|____|____|____|____| | | | | | | | | | | | | | 5 | 6 | 7 | 8 | 9 | | | | | | | |____|____|____|____|____| Each section is denoted by a number from 0 to 9 as illustrated above. For example, if the second column of the top row was desired, the section would be defined as: -sec 1 To prevent HUD objects from displaying over each other and causing a clutter of letters, each row has a defined visibility precedence, where each section would have a visibility priority level. Depending on each priority level, when the screen space begins to shrink to a point where the section widths of a given row begin to collide, the HUD automatically compensates for this by removing the sections of least priority. These sections are made invisible and a warning is issued to inform the user of the removal. This continues until only the section of highest priority remains. For each row, the priorities are defined as follows. Using the top row as an example: Section 0, has the highest priority, followed by Section 4, making the outermost sections of highest priority. Next in the list is Section 2, and lastly Sections 1 and 3 are of the equal and least priority. This priority structure can be applied to the bottom row as well. The two outermost sections have the highest priority, followed by the middle section, and finally the remaining two sections are of lowest priority. This means that as the viewport gradually decreases in width to the point where sections in the top row begin to overlap, sections 1 and 3 will be removed from view first, followed by section 2, and finally section 4. A similar note is provided below for the block layout.
setOption (so)		unicode, unicode
	This flag will edit the option specified by the first string. Current options are: smpPolyCount - “cage” or “smp” - in smooth mesh preview, determines the poly count display
showGrid (sg)		bool
	This flag will toggle the display of the grid lines of the HUD layout.
visible (vis)		bool
	Sets the visibility of the Heads-Up Display on and off.

Derived from mel command maya.cmds.headsUpDisplay

Example:

import pymel.core as pm

#
#Define a procedure that returns a value to be used by the Heads Up Display
#
def objectPosition(*args):
        try:
                selectedNodes = pm.selectedNodes()
                mainObj = selectedNodes[-1]
                positionList = pm.getAttr('%s.translate' % mainObj)
                return positionList[0]
        except:
                return (0.0,0.0,0.0)
#
#Now, create a HUD object to display the return value of the above procedure
#
#Attributes:
#
#        - Section 1, block 0, represents the top second slot of the view.
#        - Set the blockSize to "medium", instead of the default "small"
#        - Assigned the HUD the label: "Position"
#        - Defined the label font size to be large
#        - Assigned the HUD a command to run on a SelectionChanged trigger
#        - Attached the attributeChange node change to the SelectionChanged trigger
#          to allow the update of the data on attribute changes.
#
pm.headsUpDisplay( 'HUDObjectPosition', section=1, block=0, blockSize='medium', label='Position', labelFontSize='large', command=objectPosition, event='SelectionChanged', nodeChanges='attributeChange' )
# Result: u'30' #
#
#Create a preset HUD object to display the camera names.
#
#Attributes:
#
#    - Section 2, block 0, represents the top middle slot of the view.
#    - Using blockalign, the HUD object is centered in the middle of the block
#    - Setting a dw of 50, allocates a space of 50 pixels for the data to reside in.
#    - Finally setting the preset to "cameraNames", selects a preset which will
#      automatically insert the associated data into the data field.
#
pm.headsUpDisplay( 'HUDCameraName', s=2, b=0, ba='center', dw=50, pre='cameraNames')
# Result: u'31' #
#
#Now, remove these two HUDs. Both can be removed in three ways: name, ID or position.
#The following examples will demonstrate removal by name and position
#
pm.headsUpDisplay( 'HUDObjectPosition', rem=True )
# Result: [u'HUDObjectPosition'] #
pm.headsUpDisplay( rp=(7, 0) )
# Result: [7, 0] #