Transform and Coordinate Spaces

ZoomBorder maintains a transform matrix that maps content coordinates into viewport coordinates. Most higher-level APIs are thin wrappers over that model.

The Three Views Of Space

content space: the original coordinate system of the child control
viewport space: the visible region inside the ZoomBorder
screen-like vectors and sizes: transformed measurements derived from the active matrix

Core Conversion APIs

Use these methods instead of manually duplicating matrix math:

Avalonia.Controls.PanAndZoom.ZoomBorder.ViewportToContent(Avalonia.Point)
Avalonia.Controls.PanAndZoom.ZoomBorder.ContentToViewport(Avalonia.Point)
Avalonia.Controls.PanAndZoom.ZoomBorder.ViewportToContent(Avalonia.Rect)
Avalonia.Controls.PanAndZoom.ZoomBorder.ContentToViewport(Avalonia.Rect)
Avalonia.Controls.PanAndZoom.ZoomBorder.GetContentToScreenMatrix
Avalonia.Controls.PanAndZoom.ZoomBorder.GetScreenToContentMatrix

These become important when:

zooming to a region selected in viewport space
showing overlays aligned with content coordinates
translating pointer positions into domain coordinates on a diagram or image

Matrix Helpers

Avalonia.Controls.PanAndZoom.MatrixHelper contains reusable helpers such as:

Translate(...)
ScaleAt(...)
Rotation(...)
TransformPoint(...)

It is useful when you build custom overlays or test matrix calculations separately from the control.

Visible Area Queries

Two methods are especially important for viewport-aware logic:

Avalonia.Controls.PanAndZoom.ZoomBorder.GetVisibleContentBounds
Avalonia.Controls.PanAndZoom.ZoomBorder.GetViewportBounds

They allow item culling, overlay rendering, and "jump to region" UX without duplicating coordinate conversion code.