a:prstGeom (Preset Geometry)

Description

a:prstGeom defines a shape using one of the preset geometry types (built-in shapes). It is defined in ECMA-376 Part 1 §20.1.7.1.

Preset geometries include:

• Basic: rect, ellipse, diamond, triangle, rtTriangle
• Arrows: leftArrow, rightArrow, upArrow, downArrow
• Symbols: star5, star6, star7, star8, plus, x, cross
• Callouts: callout1, callout2, callout3
• Many others: pentagon, hexagon, octagon, parallelogram, etc.

The prst attribute specifies which preset shape to use. Adjustment lists (a:avLst) allow fine-tuning of shape proportions.

Attributes

Examples

Rectangle Preset Geometry

<a:prstGeom prst="rect">
  <a:avLst/>
</a:prstGeom>

using DocumentFormat.OpenXml.Drawing;

var presetGeometry = new PresetGeometry { Preset = ShapeTypeValues.Rectangle };
presetGeometry.Append(new AdjustValueList());

Five-Point Star with Adjustment Values

<a:prstGeom prst="star5">
  <a:avLst>
    <a:adj rad="100000"/>
  </a:avLst>
</a:prstGeom>

var presetGeometry = new PresetGeometry { Preset = ShapeTypeValues.Star5 };
var adjLst = new AdjustValueList();
adjLst.Append(new AdjustValue { Val = 100000 });  // Star point sharpness
presetGeometry.Append(adjLst);

Right Arrow Preset Geometry

<a:prstGeom prst="rightArrow">
  <a:avLst/>
</a:prstGeom>

var presetGeometry = new PresetGeometry { Preset = ShapeTypeValues.RightArrow };
presetGeometry.Append(new AdjustValueList());

Rounded Rectangle with Corner Rounding

<a:prstGeom prst="roundRect">
  <a:avLst>
    <a:adj rad="50800"/>
  </a:avLst>
</a:prstGeom>

var presetGeometry = new PresetGeometry { Preset = ShapeTypeValues.RoundRectangle };
var adjLst = new AdjustValueList();
adjLst.Append(new AdjustValue { Val = 50800 });  // Corner radius
presetGeometry.Append(adjLst);

Notes

• The a:avLst (adjustment value list) is required but can be empty for shapes without adjustable parameters.
• Common preset types include rect, ellipse, diamond, triangle, star5, leftArrow, rightArrow, pentagon, hexagon, plus, cross.
• Each preset geometry type supports different adjustment parameters; refer to the ECMA-376 spec for type-specific adjustments.
• The shape dimensions are controlled by a:xfrm (transform) in the parent a:spPr element, not by the geometry itself.
• Preset geometries are resolution-independent; they scale smoothly to any size.
• Over 100 preset shape types are available in the ECMA-376 standard.