Geometry Engine

PowerPoint shapes are not stored as paths - they're defined by a shape preset (one of 187+) plus adjustment handles, evaluated through the OOXML DrawingML guide-formula language to produce coordinates. The geometry module turns all of that into SVG paths and clip paths the renderer can use.

This is an overview of what the module does and the public helpers it exports (re-exported from pptx-viewer-core). It powers the React viewer's shape rendering and the headless SVG export.

What it handles

Concern	Detail
Preset shapes	187+ definitions (rect, roundRect, arrows, stars, callouts, flowchart, etc.) with adjustment handles.
Clip paths	Pre-computed and adjustment-aware SVG clip paths for every preset.
Guide formulas	Full OOXML DrawingML formula evaluator (+/-, */div, val, abs, sqrt, sin/cos/tan, at2, min/max, mod, pin, if, ?:) over built-in variables (w, h, l/t/r/b, wd2, hd2, cd2/cd4/cd8) and adjustment handles (adj, adj1, …).
Custom geometry	Parsing of arbitrary <a:custGeom> paths.
Connectors	Routing and path generation for straight / bent / curved connectors.
Transforms	Element position, rotation, and flip transforms.
Boolean ops	Union / intersect / subtract / fragment of shapes (for merged geometry).
Freeform / callouts	Freeform path building, Douglas–Peucker simplification, callout leader-line geometry.

Resolving a shape to a clip path

The main entry points convert a shape (by preset type) into an SVG clip path. Adjustment-aware variants honour the shape's draggable handles:

import {
	getShapeType,
	getShapeClipPath,
	getAdjustmentAwareShapeClipPath,
	getShapeClipPathFromPreset,
	getPresetShapeClipPath,
} from 'pptx-viewer-core';

const clip = getShapeClipPath(element);

These return CSS/SVG clip-path values used to mask the rendered element box.

Evaluating preset shapes and guide formulas

For full path data (not just a clip), evaluate the preset against a width/height and adjustment values:

import {
	evaluatePresetShape,
	lookupPresetShape,
	evaluateGuides,
	parseGuideDefinitions,
	parseAdjustmentValues,
	evaluateGeometryPaths,
	resolveCoordinate,
	createBuiltinVariables,
	ooxmlArcToSvg,
} from 'pptx-viewer-core';

Helper	Purpose
lookupPresetShape(name)	Look up a preset definition by OOXML shape name.
evaluatePresetShape(...)	Evaluate a preset to path geometry (PresetShapeEvaluationResult).
parseGuideDefinitions / parseAdjustmentValues	Parse <a:gd> guides and adjustment values from shape XML.
createBuiltinVariables	Seed w, h, l/t/r/b, wd2, … for evaluation.
evaluateGuides	Run the formula evaluator over a guide set.
evaluateGeometryPaths / resolveCoordinate	Produce path commands / resolve a single coordinate.
ooxmlArcToSvg	Convert an OOXML arc segment to an SVG arc.

The preset tables themselves are exported: PRESET_SHAPE_GEOMETRY_TABLE, PRESET_SHAPE_CLIP_PATHS, PRESET_SHAPE_DEFINITIONS, and PRESET_SHAPE_CATEGORY_LABELS.

Connectors

import { getConnectorPathGeometry, getConnectorAdjustment } from 'pptx-viewer-core';
import type { ConnectorPathGeometry } from 'pptx-viewer-core';

const geom = getConnectorPathGeometry(connectorElement);

getConnectorPathGeometry routes straight / bent / curved connectors and returns the path geometry for rendering.

Transforms

import { getElementTransform, getTextCompensationTransform } from 'pptx-viewer-core';

const transform = getElementTransform(element); // position / rotation / flip

Boolean operations and freeform

For merged shapes and freeform drawing, the module exports boolean helpers and path utilities:

import {
	unionShapes,
	intersectShapes,
	subtractShapes,
	combineShapes,
	svgPathToPolygons,
	polygonsToSvgPath,
	FreeformPathBuilder,
	douglasPeucker,
	catmullRomToBezier,
} from 'pptx-viewer-core';

And callout geometry:

import {
	isCalloutShape,
	getCalloutTier,
	getCalloutLeaderLineGeometry,
	buildCalloutLeaderLineSvgPath,
} from 'pptx-viewer-core';

Rendering

You rarely call these directly when using the React package - they're wired into the renderer. Reach for them when building a custom renderer or generating geometry outside the viewer (e.g. server-side). For the visual output, see /core/svg-export and /react/.