Table of Contents

• 1. currentpoint
  • 1.1. Syntax
  • 1.2. Stack Effects
  • 1.3. Description
  • 1.4. PostScript Level
  • 1.5. Examples
  • 1.6. Common Use Cases
    • 1.6.1. Implementing Relative Operations
    • 1.6.2. Saving and Restoring Position
    • 1.6.3. Computing Path Dimensions
    • 1.6.4. Creating Custom Path Operations
  • 1.7. Common Pitfalls
  • 1.8. Error Conditions
  • 1.9. Implementation Notes
  • 1.10. Coordinate Transformation
  • 1.11. Performance Considerations
  • 1.12. See Also

1. currentpoint

Returns the x and y coordinates of the current point.

1.1. Syntax

- currentpoint → x y

1.2. Stack Effects

Table 1. Before

Level	Object
(empty)	No operands required

Table 2. After

Level	Object
1	y (number - current point y-coordinate)
0	x (number - current point x-coordinate)

1.3. Description

currentpoint returns the x and y coordinates of the current point in the graphics state (i.e., the trailing endpoint of the current path).

If the current point is undefined because the current path is empty, currentpoint executes the [nocurrentpoint] error.

The current point is reported in the user coordinate system. Points entered into a path are immediately converted to device coordinates by the current transformation matrix (CTM); existing points are not changed by subsequent modifications to the CTM. currentpoint computes the user space coordinate that corresponds to the current point according to the current value of the CTM. If a current point is set and then the CTM is changed, currentpoint will report a different position in user space than it did before.

1.4. PostScript Level

Level 1 and later

1.5. Examples

Getting current position

newpath
100 150 moveto
currentpoint             % Returns: 100 150
pop pop

Saving current position

newpath
100 100 moveto
200 200 lineto

currentpoint             % Get endpoint
/y exch def
/x exch def

% Can now return to this point
50 50 lineto
x y lineto               % Back to (200, 200)

Relative positioning

100 100 moveto
currentpoint             % 100 100
exch 50 add exch         % Add 50 to x
lineto                   % Draw to (150, 100)

1.6. Common Use Cases

1.6.1. Implementing Relative Operations

/rmoveto_manual {
  % dx dy
  /dy exch def
  /dx exch def
  currentpoint
  dy add exch
  dx add exch
  moveto
} def

100 100 moveto
50 30 rmoveto_manual     % Moves to (150, 130)

1.6.2. Saving and Restoring Position

/savecurrentpoint {
  currentpoint
  /savedY exch def
  /savedX exch def
} def

/restorecurrentpoint {
  savedX savedY moveto
} def

100 100 moveto
savecurrentpoint
200 200 lineto
restorecurrentpoint       % Back to (100, 100)

1.6.3. Computing Path Dimensions

/pathLength {
  % Approximates total path length
  /totalLength 0 def
  {
    /y1 exch def /x1 exch def
    currentpoint
    /y0 exch def /x0 exch def
    x1 x0 sub dup mul y1 y0 sub dup mul add sqrt
    totalLength add /totalLength exch def
    x1 y1 moveto
  } % line procedure
  {} % curve procedure (simplified)
  {} % move procedure
  {} % close procedure
  pathforall
  totalLength
} def

1.6.4. Creating Custom Path Operations

/drawArrowhead {
  % Draws arrowhead at current point
  % Assumes path direction is known
  gsave
  currentpoint translate   % Move origin to current point
  % Draw arrowhead at origin
  newpath
  0 0 moveto
  -10 5 lineto
  -10 -5 lineto
  closepath
  fill
  grestore
} def

100 100 moveto
200 200 lineto
drawArrowhead

1.7. Common Pitfalls

Requires Current Point - currentpoint fails if the path is empty or only contains moveto operations that were superseded.

newpath
currentpoint             % Error: nocurrentpoint

CTM Affects Results - The coordinates returned are in current user space. Changing the CTM changes the reported coordinates.

100 100 moveto
currentpoint             % Returns: 100 100

2 2 scale                % Change CTM
currentpoint             % Returns: 50 50 (in new user space)

Not Affected by gsave/grestore - The current point is part of the graphics state and is saved/restored by gsave/grestore.

100 100 moveto
gsave
200 200 lineto
currentpoint             % Returns: 200 200
grestore
currentpoint             % Returns: 100 100 (restored)

Use for Position-Dependent Drawing - currentpoint is essential for drawing elements that depend on the current path position, like arrowheads or labels.

1.8. Error Conditions

Error	Condition
[nocurrentpoint]	Current path is empty (no current point defined)
[stackoverflow]	Operand stack is full (cannot push two values)
[undefinedresult]	Numeric overflow in coordinate transformation

1.9. Implementation Notes

• Returns coordinates in current user space

• Coordinates are computed from device space using inverse CTM

• May have rounding errors due to coordinate transformations

• The current point exists only after path construction operations

• Superseded moveto operations don’t leave a current point

1.10. Coordinate Transformation

The current point is stored internally in device space. currentpoint performs this transformation:

device_point → CTM⁻¹ → user_point

This means:

matrix currentmatrix /ctm exch def
100 100 moveto            % Set point in user space
currentpoint              % Get it back
% Stack: 100 100 (approximately, may have rounding)

1.11. Performance Considerations

• Very fast operation

• Involves matrix inversion (minimal overhead)

• No memory allocation

• Useful for avoiding redundant coordinate calculations

1.12. See Also

• moveto - Set current point (absolute)

• rmoveto - Set current point (relative)

• lineto - Add line to current point

• newpath - Clear current path