Table of Contents

• 1. Description
• 2. Syntax
  • 2.1. Stack Effect
• 3. Parameters
• 4. Return Values
• 5. Examples
  • 5.1. Basic Truncation
  • 5.2. Extracting Integer Part
• 6. Related Commands
• 7. PostScript Level
• 8. Error Conditions
• 9. See Also

Truncates a number toward zero by removing its fractional part.

1. Description

The truncate operator pops a number from the operand stack and pushes the integer part of that number, discarding the fractional part. Truncation is always toward zero (for positive numbers, rounds down; for negative numbers, rounds up). The type of the result is the same as the type of the operand.

This is a Level 1 operator, available in all PostScript implementations.

2. Syntax

num1 truncate num2

2.1. Stack Effect

Table 1. Before Execution

Position	Content
Top	num1 (integer or real) - Number to truncate

Table 2. After Execution

Position	Content
Top	num2 (integer or real) - Integer part of num1 (same type)

3. Parameters

num1

Any number (integer or real)

4. Return Values

num2

The integer part of num1 with fractional part removed (type matches num1)

5. Examples

5.1. Basic Truncation

% Positive numbers truncate down
3.2 truncate   % → 3.0
3.9 truncate   % → 3.0

% Negative numbers truncate up (toward zero)
-4.8 truncate  % → -4.0 (toward zero)
-4.1 truncate  % → -4.0

% Integers unchanged
99 truncate    % → 99

5.2. Extracting Integer Part

% Get integer and fractional parts
/getParts {  % num -> intPart fracPart
    dup truncate     % num intPart
    2 copy sub       % num intPart fracPart
    3 1 roll pop     % intPart fracPart
} def

3.7 getParts   % → 3.0 0.7
-5.3 getParts  % → -5.0 -0.3

6. Related Commands

• ceiling - Round up

• floor - Round down

• round - Round to nearest

7. PostScript Level

Available in: PostScript Level 1 and higher

8. Error Conditions

stackunderflow

The operand stack is empty.

typecheck

The operand is not a number.

9. See Also

• Arithmetic and Math - All arithmetic operators