`pdfCalcWidthHeight`

Compute the missing dimension when scaling an object

double __stdcall pdfCalcWidthHeight(PPDF IPDF, double OrgWidth, double OrgHeight, double ScaledWidth, double ScaledHeight);

Delphi

function pdfCalcWidthHeight(const IPDF: PPDF; OrgWidth, OrgHeight, ScaledWidth, ScaledHeight: Double): Double; stdcall;

Purpose. Compute the missing dimension when scaling an object proportionally: given one target dimension, return the other, preserving OrgWidth/OrgHeight's aspect ratio. A pure math utility — does not consult IPDF at all despite accepting the parameter.

Description. If ScaledWidth > 0, returns the matching height (ScaledWidth * OrgHeight / OrgWidth); else if ScaledHeight > 0, returns the matching width (ScaledHeight * OrgWidth / OrgHeight); else 0.0. A source comment notes this corrects an earlier bug where the ScaledHeight branch merely echoed ScaledHeight back instead of computing the matching width.

Parameters.

Parameter	Description
`IPDF`	Accepted but not consulted — pure math, works with any handle including an invalid one.
`OrgWidth`, `OrgHeight`	Original dimensions; both must be `> 0` or the result is `0.0`.
`ScaledWidth`	If `> 0`, the known target width — the function returns the matching height.
`ScaledHeight`	Used only if `ScaledWidth <= 0`; if `> 0`, the function returns the matching width.

Return value. The computed matching dimension; 0.0 if OrgWidth/ OrgHeight aren't both positive, or neither ScaledWidth nor ScaledHeight is positive.

C# (P/Invoke)

wrappers/dotnet/LumasPdf.cs

public static extern double pdfCalcWidthHeight(IntPtr IPDF, double OrgWidth, double OrgHeight, double ScaledWidth, double ScaledHeight);

Area

Core SDK