zSlider 1.1

### zSlider 1.1 by heyw ###
###changes ####
### Updated to use matrix world space coordinates. This allows the script to work on parented or animated cameras.
### 1.1 ppdateby Mars ####
# Usage:

#     1. Use the following python command to load the script or add it to your userSetup.py and restart maya

#        import zSlider

#     2. In the Hotkey Editor create 2 Runtime Commands with the start/stop
#     functions(the language should be set to python):

#         zSlider.start()

#         and

#         zSlider.stop()

#     set the entry with 'zSliderStop()' to 'On Release'
#     Assign both commands to the same key.

#     3. Press and hold the hotkey while moving the mouse left to right to slide the
#     current selection towards/away from the camera.

#     4. The start has function 3 optional flags, these are the default values

#         zSlider.start(slideMode=0, slideSpeed=1000, doScaling=0)

#     slideMode=0
#         the selection slides linearly with the amount of mouse movement
#     slideMode=1
#         the sliding has an exponential feel, as objects get closer they slide
#         slower, further they slide faster

#     'slideSpeed' is the how many pixels the mouse must move to slide the selection
#     a given distance, larger values = slower sliding.

#     doScaling=0
#         scaling is disabled
#     doScaling=1
#         the object is scaled in proportion to the distance it's moved. The result is the
#         object maintains its apparent size from the camera's perspective as it slides.

#     These can be used to assign multiple hotkeys with different behavior. ie. for general use
#     assigning the 'a' key with:

#         zSlider.start(slideSpeed=500)

#     then for fine tuning assigning shift+a with:

#         zSlider.start(slideSpeed=4000)

#     IMPORTANT: If the tool gets stuck on use the following mel command to kill all script jobs:

#         scriptJob -ka;


import maya.cmds as cmds
import maya.mel as mel
from ctypes import windll, Structure, c_long, byref


class POINT(Structure):
    _fields_ = [("x", c_long), ("y", c_long)]

def getCursorPos():
    pt = POINT()
    windll.user32.GetCursorPos(byref(pt))
    return([pt.x,pt.y])

def start(slideMode=0, slideSpeed=8000, doScaling=0):

    # Find camera and get ws position
    panel = cmds.getPanel(underPointer=True)

    if panel not in cmds.getPanel(type='modelPanel'):
        print('model panel not found')
        return
    cam = cmds.modelPanel(panel,q=True,cam=True)
    camPos = cmds.getAttr(cam+'.worldMatrix')

    # Store current offset for selected objects
    sel = cmds.ls(sl=True)
    selOffsets = []
    for item in sel:
        pos = cmds.getAttr(item+'.worldMatrix')
        scale = cmds.xform(item,q=True,s=True,r=True)
        selOffsets.append([pos[12]-camPos[12],pos[13]-camPos[13],pos[14]-camPos[14], scale[0],scale[1],scale[2]])
        print selOffsets

    mouseX = getCursorPos()[0]

    cmds.undoInfo(openChunk=True)

    job = cmds.scriptJob(ie=('tick('+str(mouseX)+', '+str(camPos)+', '+str(map(lambda x: str(x), sel))+', '+str(selOffsets)+', '+str(slideMode)+', '+str(float(slideSpeed))+', '+str(doScaling)+')'));
    mel.eval('global int $zSliderJob='+str(job))

def stop():
    job = mel.eval('$tempMelVar=$zSliderJob')
    cmds.scriptJob(kill=job)
    cmds.undoInfo(closeChunk=True)

def tick(mouseX, camPos, sel, offsets, mode, speed, doScaling):
    slideMode = 0
    s = 1+((mouseX-getCursorPos()[0])/speed)
    if slideMode is 0: f = s
    if slideMode is 1: f = 1/s

    for x, offset in enumerate(offsets):
        newPos = [f*offset[0]+camPos[12],f*offset[1]+camPos[13],f*offset[2]+camPos[14]]
        newScale = [s*offset[3],s*offset[4],s*offset[5]]
        cmds.move(newPos[0],newPos[1],newPos[2], sel[x],ws=True,spr=True)
        if doScaling:
            cmds.scale(newScale[0],newScale[1],newScale[2], sel[x])