Line/Connector Shape

Lines are a sub-category of auto shape that differ in certain properties and behaviors. In particular, they have a start point and end point in addition to extents (left, top, width, height).

Connectors are based on the <p:cxnSp> element and have one of a handful of different preset geometry values, such as line. Freeform connectors, despite the name, are not connectors, and are a custom geometry shape based on the p:sp element.

Connectors can be “connected” to an auto shape such that a connected end point remains connected when the auto shape is moved. This relies on a concept of “connection points” on the auto shape. These connections points are preset features of the auto shape, similar to how adjustment points are pre-defined. Connection points are identified by index.

Connector shapes do not have a text frame and cannot have text that is anchored to the shape.

Design Issues

• See how PowerPoint interprets the remaining connector types like bentConnector2

Unimplemented Scope

• Connector.shape_type = MSO_LINE
• BaseShape.is_connector + ConnectorShape.is_connector (not yet implemented)
• [ ] see how a connector returns for connector.AutoShapeType in MS API.

PowerPoint behaviors

• Once connected, moving the target shape moves the connector the same amount, however, the relative position of the connector end-point is not adjusted to align to the connection point; rather, the relative offset is maintained.

  Also, when the connector is selected, the connected point is highlighted in red, even though it is not coincident with the connection point.

• Arrow heads are not a direct property of a connector, despite perhaps appearing so in the UI. Line endings are a property of the line style of the connector (and other shapes).

MS API

Shapes Object Members

• AddConnector(Type, BeginX, BeginY, EndX, EndY)

MsoConnectorType Enumeration

msoConnectorCurve	3	Curved connector.
msoConnectorElbow	2	Elbow connector.
msoConnectorStraight	1	Straight line connector.
msoConnectorTypeMixed	-2	Return only; indicates combination of states.

Protocols

Properties:

>>> connector.is_connector
True
>>> connector.type
MSO_SHAPE_TYPE.LINE
>>> connector.start_x
914400
>>> connector.end_y
914400
>>> connector.adjustments
<pptx.shapes.shared.Adjustments instance at 0x123456789>

Creation protocol:

>>> line = shapes.add_connector(
...     MSO_CONNECTOR.STRAIGHT, start_x, start_y, end_x, end_y
... )

MS API Protocol

Behaviors

UI display

Connector shapes do not display a bounding box when selected in the UI. Rather their start and end points are highlighted with a small gray circle that can be moved. If there is an adjustment, such as a mid-point, it is indicated in the normal way with a small yellow diamond. These endpoints and adjustment diamond cannot be individually selected.

Naming

What determines the name automatically applied to a line or connector shape? Can it change after shape creation, for example by applying an arrowhead?

Enumerations

MsoConnectorType

http://msdn.microsoft.com/en-us/library/office/ff860918(v=office.15).aspx

Name	Value	Description
msoConnectorCurve	3	Curved connector.
msoConnectorElbow	2	Elbow connector.
msoConnectorStraight	1	Straight line connector.
msoConnectorTypeMixed	-2	Return value only; indicates a combination of the other states.

Specimen XML

Default connector shapes inserted from PowerPoint UI.

Straight line (Connector):

<p:cxnSp>
  <p:nvCxnSpPr>
    <p:cNvPr id="3" name="Straight Connector 2"/>
    <p:cNvCxnSpPr/>
    <p:nvPr/>
  </p:nvCxnSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="611560" y="620688"/>
      <a:ext cx="914400" cy="914400"/>
    </a:xfrm>
    <a:prstGeom prst="line">
      <a:avLst/>
    </a:prstGeom>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
</p:cxnSp>

Straight arrow Connector:

<p:cxnSp>
  <p:nvCxnSpPr>
    <p:cNvPr id="7" name="Straight Arrow Connector 6"/>
    <p:cNvCxnSpPr/>
    <p:nvPr/>
  </p:nvCxnSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="950964" y="1673307"/>
      <a:ext cx="1257921" cy="0"/>
    </a:xfrm>
    <a:prstGeom prst="straightConnector1">
      <a:avLst/>
    </a:prstGeom>
    <a:ln>
      <a:tailEnd type="arrow"/>
    </a:ln>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
</p:cxnSp>

Straight segment jointed connector:

<p:cxnSp>
  <p:nvCxnSpPr>
    <p:cNvPr id="9" name="Elbow Connector 8"/>
    <p:cNvCxnSpPr/>
    <p:nvPr/>
  </p:nvCxnSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="950964" y="2124739"/>
      <a:ext cx="1257921" cy="415317"/>
    </a:xfrm>
    <a:prstGeom prst="bentConnector3">
      <a:avLst/>
    </a:prstGeom>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
</p:cxnSp>

Curved (S-like) connector:

<p:cxnSp>
  <p:nvCxnSpPr>
    <p:cNvPr id="11" name="Curved Connector 10"/>
    <p:cNvCxnSpPr/>
    <p:nvPr/>
  </p:nvCxnSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="950964" y="2925277"/>
      <a:ext cx="1257921" cy="619967"/>
    </a:xfrm>
    <a:prstGeom prst="curvedConnector3">
      <a:avLst/>
    </a:prstGeom>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
</p:cxnSp>

Freeform connector:

<p:sp>
  <p:nvSpPr>
    <p:cNvPr id="12" name="Freeform 11"/>
    <p:cNvSpPr/>
    <p:nvPr/>
  </p:nvSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="981058" y="4086962"/>
      <a:ext cx="1372277" cy="686176"/>
    </a:xfrm>
    <a:custGeom>
      <a:avLst/>
      <a:gdLst>
        <a:gd name="connsiteX0" fmla="*/ 0 w 1372277"/>
        <a:gd name="connsiteY0" fmla="*/ 0 h 686176"/>
        <a:gd name="connsiteX1" fmla="*/ 379182 w 1372277"/>
        <a:gd name="connsiteY1" fmla="*/ 306973 h 686176"/>
        <a:gd name="connsiteX2" fmla="*/ 944945 w 1372277"/>
        <a:gd name="connsiteY2" fmla="*/ 48152 h 686176"/>
      </a:gdLst>
      <a:ahLst/>
      <a:cxnLst>
        <a:cxn ang="0">
          <a:pos x="connsiteX0" y="connsiteY0"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX1" y="connsiteY1"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX2" y="connsiteY2"/>
        </a:cxn>
      </a:cxnLst>
      <a:rect l="l" t="t" r="r" b="b"/>
      <a:pathLst>
        <a:path w="1372277" h="686176">
          <a:moveTo>
            <a:pt x="0" y="0"/>
          </a:moveTo>
          <a:cubicBezTo>
            <a:pt x="110845" y="149474"/>
            <a:pt x="221691" y="298948"/>
            <a:pt x="379182" y="306973"/>
          </a:cubicBezTo>
          <a:cubicBezTo>
            <a:pt x="536673" y="314998"/>
            <a:pt x="811529" y="4012"/>
            <a:pt x="944945" y="48152"/>
          </a:cubicBezTo>
        </a:path>
      </a:pathLst>
    </a:custGeom>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
  <p:txBody>
    <a:bodyPr rtlCol="0" anchor="ctr"/>
    <a:lstStyle/>
    <a:p>
      <a:pPr algn="ctr"/>
      <a:endParaRPr lang="en-US"/>
    </a:p>
  </p:txBody>
</p:sp>

Completely free-form line:

<p:sp>
  <p:nvSpPr>
    <p:cNvPr id="13" name="Freeform 12"/>
    <p:cNvSpPr/>
    <p:nvPr/>
  </p:nvSpPr>
  <p:spPr>
    <a:xfrm>
      <a:off x="1005133" y="5483390"/>
      <a:ext cx="1360239" cy="379203"/>
    </a:xfrm>
    <a:custGeom>
      <a:avLst/>
      <a:gdLst>
        <a:gd name="connsiteX0" fmla="*/ 0 w 1360239"/>
        <a:gd name="connsiteY0" fmla="*/ 0 h 379203"/>
        <a:gd name="connsiteX1" fmla="*/ 0 w 1360239"/>
        <a:gd name="connsiteY1" fmla="*/ 0 h 379203"/>
        <a:gd name="connsiteX2" fmla="*/ 96300 w 1360239"/>
        <a:gd name="connsiteY2" fmla="*/ 6020 h 379203"/>
        <a:gd name="connsiteX3" fmla="*/ 138431 w 1360239"/>
        <a:gd name="connsiteY3" fmla="*/ 18058 h 379203"/>
        <a:gd name="connsiteX4" fmla="*/ 222694 w 1360239"/>
        <a:gd name="connsiteY4" fmla="*/ 24077 h 379203"/>
        <a:gd name="connsiteX5" fmla="*/ 511594 w 1360239"/>
        <a:gd name="connsiteY5" fmla="*/ 24077 h 379203"/>
      </a:gdLst>
      <a:ahLst/>
      <a:cxnLst>
        <a:cxn ang="0">
          <a:pos x="connsiteX0" y="connsiteY0"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX1" y="connsiteY1"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX2" y="connsiteY2"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX3" y="connsiteY3"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX4" y="connsiteY4"/>
        </a:cxn>
        <a:cxn ang="0">
          <a:pos x="connsiteX5" y="connsiteY5"/>
        </a:cxn>
      </a:cxnLst>
      <a:rect l="l" t="t" r="r" b="b"/>
      <a:pathLst>
        <a:path w="1360239" h="379203">
          <a:moveTo>
            <a:pt x="0" y="0"/>
          </a:moveTo>
          <a:lnTo>
            <a:pt x="0" y="0"/>
          </a:lnTo>
          <a:cubicBezTo>
            <a:pt x="32100" y="2007"/>
            <a:pt x="64408" y="1860"/>
            <a:pt x="96300" y="6020"/>
          </a:cubicBezTo>
          <a:cubicBezTo>
            <a:pt x="110783" y="7909"/>
            <a:pt x="123972" y="15992"/>
            <a:pt x="138431" y="18058"/>
          </a:cubicBezTo>
          <a:cubicBezTo>
            <a:pt x="166307" y="22040"/>
            <a:pt x="194606" y="22071"/>
            <a:pt x="222694" y="24077"/>
          </a:cubicBezTo>
          <a:cubicBezTo>
            <a:pt x="333136" y="60893"/>
            <a:pt x="138800" y="-1634"/>
            <a:pt x="511594" y="24077"/>
          </a:cubicBezTo>
          <a:lnTo>
            <a:pt x="1360239" y="343089"/>
          </a:lnTo>
        </a:path>
      </a:pathLst>
    </a:custGeom>
  </p:spPr>
  <p:style>
    <a:lnRef idx="2">
      <a:schemeClr val="accent1"/>
    </a:lnRef>
    <a:fillRef idx="0">
      <a:schemeClr val="accent1"/>
    </a:fillRef>
    <a:effectRef idx="1">
      <a:schemeClr val="accent1"/>
    </a:effectRef>
    <a:fontRef idx="minor">
      <a:schemeClr val="tx1"/>
    </a:fontRef>
  </p:style>
  <p:txBody>
    <a:bodyPr rtlCol="0" anchor="ctr"/>
    <a:lstStyle/>
    <a:p>
      <a:pPr algn="ctr"/>
      <a:endParaRPr lang="en-US"/>
    </a:p>
  </p:txBody>
</p:sp>

Analysis

• The p:style element represents indirection of the connector visual attributes to the theme part.
• What’s up with the p:style element? Does that have to be there? What happens if we just leave that out? Is the accent1 default universal enough to pop in there without consideration?
• Seems like the most common lines are connectors
• Connectors are a distinct shape type. They are very similar to regular <p:sp>-based auto shapes, but lack a text frame.
• Hypothesis: There are really two types, connectors and free-form.
  • Connectors are based on the <p:cxnSp> element and have a preset geometry (<a:prstGeom> child of <p:spPr>).
  • Free-form lines are based on the <p:sp> element and have a custom geometry (<a:custGeom> child of <p:spPr>).
• Connectors don’t have a fill. Free-form shapes do. Fill of free-form shapes extends between the line and a line connecting the end points, whether present or not. Since the lines can cross, this produces some possibly surprising fill behaviors; there is no clear concept of inside and outside for such a shape.

Related Schema Definitions

<xsd:complexType name="CT_GroupShape">
  <xsd:sequence>
    <xsd:element name="nvGrpSpPr" type="CT_GroupShapeNonVisual"/>
    <xsd:element name="grpSpPr"   type="a:CT_GroupShapeProperties"/>
    <xsd:choice minOccurs="0" maxOccurs="unbounded">
      <xsd:element name="sp"           type="CT_Shape"/>
      <xsd:element name="grpSp"        type="CT_GroupShape"/>
      <xsd:element name="graphicFrame" type="CT_GraphicalObjectFrame"/>
      <xsd:element name="cxnSp"        type="CT_Connector"/>
      <xsd:element name="pic"          type="CT_Picture"/>
      <xsd:element name="contentPart"  type="CT_Rel"/>
    </xsd:choice>
    <xsd:element name="extLst" type="CT_ExtensionListModify" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="CT_Connector">
  <xsd:sequence>
    <xsd:element name="nvCxnSpPr" type="CT_ConnectorNonVisual"/>
    <xsd:element name="spPr"      type="a:CT_ShapeProperties"/>
    <xsd:element name="style"     type="a:CT_ShapeStyle"        minOccurs="0"/>
    <xsd:element name="extLst"    type="CT_ExtensionListModify" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="CT_ConnectorNonVisual">
  <xsd:sequence>
    <xsd:element name="cNvPr"      type="a:CT_NonVisualDrawingProps"/>
    <xsd:element name="cNvCxnSpPr" type="a:CT_NonVisualConnectorProperties"/>
    <xsd:element name="nvPr"       type="CT_ApplicationNonVisualDrawingProps"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="CT_Connection">
  <xsd:attribute name="id"  type="ST_DrawingElementId" use="required"/>
  <xsd:attribute name="idx" type="xsd:unsignedInt"     use="required"/>
</xsd:complexType>

<xsd:complexType name="CT_NonVisualConnectorProperties">
  <xsd:sequence>
    <xsd:element name="cxnSpLocks" type="CT_ConnectorLocking"       minOccurs="0"/>
    <xsd:element name="stCxn"      type="CT_Connection"             minOccurs="0"/>
    <xsd:element name="endCxn"     type="CT_Connection"             minOccurs="0"/>
    <xsd:element name="extLst"     type="CT_OfficeArtExtensionList" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="CT_ShapeProperties">
  <xsd:sequence>
    <xsd:element name="xfrm"                type="CT_Transform2D"            minOccurs="0"/>
    <xsd:group    ref="EG_Geometry"                                          minOccurs="0"/>
    <xsd:group    ref="EG_FillProperties"                                    minOccurs="0"/>
    <xsd:element name="ln"                  type="CT_LineProperties"         minOccurs="0"/>
    <xsd:group    ref="EG_EffectProperties"                                  minOccurs="0"/>
    <xsd:element name="scene3d"             type="CT_Scene3D"                minOccurs="0"/>
    <xsd:element name="sp3d"                type="CT_Shape3D"                minOccurs="0"/>
    <xsd:element name="extLst"              type="CT_OfficeArtExtensionList" minOccurs="0"/>
  </xsd:sequence>
  <xsd:attribute name="bwMode" type="ST_BlackWhiteMode" use="optional"/>
</xsd:complexType>

<xsd:complexType name="CT_ShapeStyle">
  <xsd:sequence>
    <xsd:element name="lnRef"     type="CT_StyleMatrixReference"/>
    <xsd:element name="fillRef"   type="CT_StyleMatrixReference"/>
    <xsd:element name="effectRef" type="CT_StyleMatrixReference"/>
    <xsd:element name="fontRef"   type="CT_FontReference"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="CT_StyleMatrixReference">
  <xsd:choice minOccurs="0">
    <xsd:element name="scrgbClr"  type="CT_ScRgbColor"/>
    <xsd:element name="srgbClr"   type="CT_SRgbColor"/>
    <xsd:element name="hslClr"    type="CT_HslColor"/>
    <xsd:element name="sysClr"    type="CT_SystemColor"/>
    <xsd:element name="schemeClr" type="CT_SchemeColor"/>
    <xsd:element name="prstClr"   type="CT_PresetColor"/>
  </xsd:choice>
  <xsd:attribute name="idx" type="ST_StyleMatrixColumnIndex" use="required"/>
</xsd:complexType>

<xsd:complexType name="CT_FontReference">
  <xsd:choice minOccurs="0">
    <xsd:element name="scrgbClr"  type="CT_ScRgbColor"/>
    <xsd:element name="srgbClr"   type="CT_SRgbColor"/>
    <xsd:element name="hslClr"    type="CT_HslColor"/>
    <xsd:element name="sysClr"    type="CT_SystemColor"/>
    <xsd:element name="schemeClr" type="CT_SchemeColor"/>
    <xsd:element name="prstClr"   type="CT_PresetColor"/>
  </xsd:choice>
  <xsd:attribute name="idx" type="ST_FontCollectionIndex" use="required"/>
</xsd:complexType>

<xsd:simpleType name="ST_DrawingElementId">
  <xsd:restriction base="xsd:unsignedInt"/>
</xsd:simpleType>

<xsd:simpleType name="ST_ShapeType">
  <xsd:restriction base="xsd:token">
    <xsd:enumeration value="line"/>
    <xsd:enumeration value="straightConnector1"/>
    <xsd:enumeration value="bentConnector2"/>
    <xsd:enumeration value="bentConnector3"/>
    <xsd:enumeration value="bentConnector4"/>
    <xsd:enumeration value="bentConnector5"/>
    <xsd:enumeration value="curvedConnector2"/>
    <xsd:enumeration value="curvedConnector3"/>
    <xsd:enumeration value="curvedConnector4"/>
    <xsd:enumeration value="curvedConnector5"/>
    ... other shape types removed ...
  </xsd:restriction>
</xsd:simpleType>