donner::editor::ViewportState Struct Reference

All viewport state for a single frame of the render pane. Plain data, side-effect-free, copyable, ~80 bytes. More...

#include "donner/editor/ViewportState.h"

Collaboration diagram for donner::editor::ViewportState:

Public Member Functions
double	pixelsPerDocUnit () const
	Screen pixels per document unit at the current zoom. With the "zoom is in screen-pixels-per-doc-unit" convention this is just zoom; the accessor exists so callers don't reach for the raw field and the definition can grow if "100%" ever stops meaning "1:1".
double	devicePixelsPerDocUnit () const
	Device pixels per document unit. Used by desiredCanvasSize and the renderer's RenderViewport.devicePixelRatio.
Vector2d	documentToScreen (const Vector2d &docPoint) const
	Map a document point to a screen-pixel point.
Vector2d	screenToDocument (const Vector2d &screenPoint) const
	Map a screen-pixel point to a document point.
Box2d	documentToScreen (const Box2d &docBox) const
	Map a document-space box to its screen-pixel AABB.
Box2d	screenToDocument (const Box2d &screenBox) const
	Map a screen-pixel box to its document-space AABB.
Box2d	imageScreenRect () const
	On-screen rectangle of the displayed document image, in screen pixels. Equal to documentToScreen(documentViewBox). Used by the AddImage call so the image always lands at the right place regardless of texture resolution.
EditorRasterViewport	rasterViewport () const
	Raster viewport the SVG renderer should produce for this editor view.
EditorRasterViewport	selectedPrewarmRasterViewport () const
	Raster viewport for idle selected-layer prewarms.
EditorRasterViewport	overviewInfillRasterViewport () const
	Low-resolution full-document raster used underneath viewport-bounded tiles.
Vector2i	desiredCanvasSize () const
	Output canvas size (in device pixels) the SVG renderer should produce. Equivalent to rasterViewport().outputSizePx.
void	zoomAround (double newZoom, const Vector2d &focalScreen)
	Set the zoom factor while holding focalScreen fixed: after this call, the document point that was previously under focalScreen is still under focalScreen. Use for Cmd+wheel, Cmd+Plus / Cmd+Minus, menu-driven zoom, and pinch-to-zoom.
void	panBy (const Vector2d &screenDelta)
	Pan by screenDelta screen pixels. After this call, every document point that was previously visible is at its previous screen position + screenDelta.
void	resetTo100Percent ()
	Reset to 100%, with the document viewBox center anchored at the pane center. After this call, pixelsPerDocUnit() == 1.0 and documentToScreen(documentViewBoxCenter()) == paneCenter. This is the initial state when the editor opens, and the target of Cmd+0 / View → Reset Zoom / View → Actual Size.
Vector2d	paneCenter () const
	Center of the render pane in screen pixels.
Vector2d	documentViewBoxCenter () const
	Center of the document viewBox in document coordinates.

Public Attributes
Vector2d	paneOrigin = Vector2d::Zero()
	Top-left of the render pane's content region in screen pixels.
Vector2d	paneSize = Vector2d::Zero()
	Size of the render pane's content region in screen pixels.
Box2d	documentViewBox
	SVG document viewBox in document coordinates.
double	devicePixelRatio = 1.0
	OS device pixel ratio (1.0 on standard displays, 2.0 on Retina). Read via glfwGetWindowContentScale.
double	zoom = 1.0
	Zoom factor in screen pixels per document unit. 1.0 means "100%": one SVG viewBox unit takes exactly one screen pixel, regardless of how many physical device pixels that is.
Vector2d	panDocPoint = Vector2d::Zero()
	Document point that should appear at panScreenPoint. Together with panScreenPoint and zoom, this fully determines the screen↔document map.
Vector2d	panScreenPoint = Vector2d::Zero()
	Screen point at which panDocPoint is anchored.

Static Public Attributes
static constexpr double	kMinZoom = 0.1
	Minimum allowed zoom (10%).
static constexpr double	kMaxZoom = 32.0
	Maximum allowed zoom (3200%).
static constexpr int	kMaxCanvasDim = 8192
	Hard cap on the rasterized canvas dimension on either axis. A 32x zoom on a 4K display would otherwise rasterize a multi-GB bitmap; this clamp keeps us in a safe place.
static constexpr int	kHighZoomRasterMarginScreenPx = 128
	Extra logical pixels around the pane that may be included in a high-zoom raster target. This keeps small pans from immediately needing a larger target while avoiding whole-document rasters at extreme zoom.
static constexpr int	kSelectedPrewarmMinOverdrawScreenPx = 256
	Minimum logical-pixel overdraw margin for selected-layer prewarm rasters.
static constexpr double	kSelectedPrewarmOverdrawPaneFraction = 0.25
	Per-axis pane fraction added on each side for selected-layer prewarm overdraw.
static constexpr int	kOverviewInfillMaxCanvasDim = 1536
	Maximum output dimension for low-resolution full-document overview infill.

Detailed Description

All viewport state for a single frame of the render pane. Plain data, side-effect-free, copyable, ~80 bytes.

Member Function Documentation

overviewInfillRasterViewport()

EditorRasterViewport donner::editor::ViewportState::overviewInfillRasterViewport ( ) const

nodiscard

Low-resolution full-document raster used underneath viewport-bounded tiles.

This is intentionally not viewport-bounded: it trades crispness for full-document coverage so zooming out does not expose transparent/checkerboard gaps while the crisp bounded render is debounced.

selectedPrewarmRasterViewport()

EditorRasterViewport donner::editor::ViewportState::selectedPrewarmRasterViewport ( ) const

nodiscard

Raster viewport for idle selected-layer prewarms.

This matches rasterViewport at normal zooms. When the base raster is viewport-bounded, the prewarm viewport adds conservative screen-space overdraw so short zoom-outs do not expose unrendered edges before the settled crisp render lands.

zoomAround()

void donner::editor::ViewportState::zoomAround	(	double	newZoom,
		const Vector2d &	focalScreen )

Set the zoom factor while holding focalScreen fixed: after this call, the document point that was previously under focalScreen is still under focalScreen. Use for Cmd+wheel, Cmd+Plus / Cmd+Minus, menu-driven zoom, and pinch-to-zoom.

newZoom is clamped to [kMinZoom, kMaxZoom].

---

The documentation for this struct was generated from the following file:

• donner/editor/ViewportState.h