AttachmentLayout Namespace Reference

Working out how much room an inline image gets, kept apart from the widget so it can be tested. More...

Functions
FVector2D	FitToBudget (FIntPoint Source, float BudgetWidth, float MaxAspect, float DpiScale)
	The size, in slate units, to draw an image of the given pixel dimensions at.
FString	WithResizeQuery (const FString &Url, FIntPoint MaxPixels)
	Ask Stream's CDN for an image no bigger than it is about to be drawn.

Detailed Description

Working out how much room an inline image gets, kept apart from the widget so it can be tested.

Function Documentation

FitToBudget()

FVector2D AttachmentLayout::FitToBudget	(	FIntPoint	Source,
		float	BudgetWidth,
		float	MaxAspect,
		float	DpiScale )

The size, in slate units, to draw an image of the given pixel dimensions at.

Fitted to BudgetWidth with the height following from the aspect ratio, which is never distorted. An image smaller than the budget is left at its own size rather than blown up, and one taller than MaxAspect times its width is scaled down as a whole so a single photo cannot fill the message list.

Parameters

Source	Pixel dimensions of the image, or anything non-positive if they are not known yet
BudgetWidth	Widest the image may be drawn, in slate units
MaxAspect	How many times its own width the image may be tall
DpiScale	Slate units per pixel, so a source's own size can be compared against the budget

WithResizeQuery()

FString AttachmentLayout::WithResizeQuery	(	const FString &	Url,
		FIntPoint	MaxPixels )

Ask Stream's CDN for an image no bigger than it is about to be drawn.

A photo straight off a phone camera runs to 25 megapixels, which is 93 MB once decoded to BGRA, for something that ends up a couple of hundred points wide. resize=clip fits the image inside the box without distorting it, and never enlarges.

Only Stream's CDN understands these, so any other URL is returned untouched rather than being sent query parameters it might reject.