Create and edit complex custom shapes

diagrams.net has a large library of pre-built shapes, but it also lets you embed your own raster and SVG images in your diagrams. While this provides you with a lot of flexibility, it doesn’t let you style raster or SVG images, except to change the colours in embedded SVG images. Because SVGs and raster images aren’t native shapes, they don’t contain the necessary information about which shapes on which to draw shadows, apply line widths, and so on.

Basic custom shapes

You can create your own custom shapes in diagrams.net by describing their geometry, connection points and styles in an XML format. The basic diagrams.net shapes use XML. Select Arrange > Insert > Shape from the diagrams.net menu to open the Edit Shape dialog where you can see the XML structure of the shape.

A complex custom shape and its code, created in diagrams.net

See how to create this basic custom shape

Tips

  • Once you have added custom shapes to the drawing canvas, you can drag and drop them onto the scratchpad or a custom shape library.
  • Edit a shape by selecting it, then click Edit Shape on the Style tab of the format panel. Note that you cannot edit all shapes, only those that are in XML format.

Create advanced custom shapes

At the end of this page you’ll find the XML to create the example used below. Copy and paste this XML into the Edit Shape dialog via Arrange > Insert > Shape in diagrams.net, and click Preview to see how more complex shapes are constructed in XSD.

A complex custom shape and its code, created in diagrams.net

Use the reference below to see how each custom shape element is defined and the order in which you need to nest these elements.

<shape>

The outer element is <shape>, which has the following attributes:

  • name - string, required. This name uniquely identifies the shape. Not currently used in diagrams.net.
  • w,h - optional decimal view bounds. This defines your co-ordinate system for the graphics operations in the shape. The default is 100,100.
  • aspect - optional string with the value of either "variable", the default, or "fixed". Fixed always renders the shape with the aspect ratio defined by the ratio w/h. Variable causes the ratio to match that of the geometry of the current vertex.
  • strokewidth - optional string containing either an integer or the string "inherit". Inherit indicates that the strokewidth of the cell is only changed when you scale it, and not when you resize it. If you use a numeric value, the strokewidth of the cell will change both when you scale and when you resize the shape. This numeric value defines the multiplier that is applied to the width. The default is "1".

<connections>

If you want to define specific fixed connection points on your custom shape, use the <connections> element. Each <constraint> element within the <connections> element defines a fixed connection point on the shape.

Constraints have the following attributes:

  • perimeter - required, either 1 or 0. A value of 0 sets the connection point where specified by x,y. A value of 1 extrapolates the position of the connection point from the center of the shape, through x,y, to the point of intersection with the perimeter of the shape.
  • x,y - the position of the fixed point relative to the bounds of the shape. These are automatically adjusted if perimeter=1. (0,0) is the top left of the shape, (0.5,0.5) is the center, (1,0.5) is the center of the right hand edge of the bounds, etc. Use values less than 0 or greater than 1 to position the fixed point outside of the shape.
  • name - optional string. A unique identifier for the port on the shape.

<background> and <foreground>

The paths used to draw the shape are split into two elements, <foreground> and <background>. If a shadow is defined, this is derived from the <background> element. Generally, the background of the shape is the line that traces the outside of the shape, but this may not always be the case.

Any stroke, fill or fillstroke of a background must be defined as the first stroke of the <foreground> element, and never in the <background> element. If the background of your shape is empty, this is not required.

The <background> element can only contain one <path>, <rect>, <roundrect> or <ellipse> element (or none). It can not contain any fill, stroke, image, text or include-shape.

Note that the state, styling and drawing in the mxGraph shapes used in diagrams.net is very close in design to that of HTML 5 canvas. Use these suggested HTML 5 tutorials for a high-level introduction to the concepts used.

State

Foreground and background elements are rendered following the concept of state. In addition to the state save/load operation, there are two other types of operations: style and draw. An applied style changes the current state.

  • <save/> - saves the current state (current style).
  • <restore/> - retrieves (loads) the last saved state from the state stack.

Style

Elements that change the colours within the current state (style) require a hash-prefixed hex color code ("#FFEA80").

  • <strokecolor> - defines the path colour when a stroke or fillstroke command is issued.
  • <fillcolor> - defines the colour inside a closed path when a fill or fillstroke command is issued.
  • <fontcolor> - defines the colour of the fonts when text is drawn.

The other style elements are as follows:

  • <alpha> - defines the alpha level, the opposite of transparency, with a range of 0.0-1.0, decimal. Use 0.0 for fully transparent and 1.0 for solid (opaque).
  • <fillalpha> - defines the fill transparency, with a range of 0.0-1.0, decimal. Use 0.0 for fully transparent and 1.0 for solid (opaque).
  • <strokealpha> - defines the stroke transparency, with a range of 0.0-1.0, decimal. Use 0.0 for fully transparent and 1.0 for solid (opaque).
  • <strokewidth> - defines the integer thickness elements drawn by stroke or fillstroke. Use fixed="1" to apply the value as-is, with no scaling.
  • <dashed> - defines the stroke style. Use "1" to enable dashes and "0" for a solid line.
  • <dashpattern> - defines the pattern of dashes and spaces on dashed strokes (when these are enabled). Use a sequence of space-separated “on, off” lengths to define the number of points used to draw a line or a space. The pattern repeats, and the default is "3 3". You can define a more complex pattern with "5 3 2 6", for example. An even number of elements in the dashpattern looks more balanced, but is not required.
  • <linejoin>, <linecap> and <miterlimit> - determine how two connecting segments of a line are joined together, how the end points of every line are drawn, and the maximum distance between the outer and inner connection points of two lines respectively. For a visual example, refer to the Mozilla page on Canvas styling. diagrams.net uses the same definitions, except that linecap is "flat" instead of Canvas’ "butt".

For font styling, the following elements are used:

  • <fontsize> - an integer.
  • <fontstyle>- an ORed bit pattern that indicates bold (1), italic (2) and underline (4). For example, bold underline is defined by the value "5".
  • <fontfamily> - a string that defines the typeface to be used.

Drawing

Most of the drawing (the lines inside the shape) is contained within a <path> element. The graphic primitives used by mxGraph in diagrams.net are very similar to that of HTML 5 Canvas.

  • <move> - to attributes, required decimals (x,y).
  • <line> - to attributes, required decimals (x,y).
  • <quad> - to required decimals (x2,y2) via the control point, required decimals (x1,y1).
  • <curve> - to required decimals (x3,y3), via control points, required decimals (x1,y1) and (x2,y2).
  • <arc> - a copy of the SVG arc command and doesn’t follow the HTML Canvas signatures. The SVG specification documentation gives the best description of its behaviour. The attributes are named identically, all decimals, and all required.
  • <close> - ends the current subpath and causes an automatic straight line to be drawn from the current point to the initial point of the current subpath.

Complex drawing

In addition to the graphics primitive operations described above, there are non-primitive operations. Use these to more easily draw some of the basic shapes:

  • <rect> - attributes "x", "y", "w", "h", all required decimals.
  • <roundrect> - attributes "x", "y", "w", "h", all required decimals. Also "arcsize" an optional decimal attribute defining how large the corner curves are.
  • <ellipse> - attributes "x", "y", "w", "h", all required decimals.

Note: these three shapes and all of their paths must be followed by either a fill, stroke, or fillstroke to render them.

<text>

Text elements have the following attributes:

  • str - the text string to display, required.
  • x and y - the decimal location (x,y) of the text element, required.
  • align - the horizontal alignment of the text element, either "left", "center" or "right". Optional, default is "left".
  • valign- the vertical alignment of the text element, either "top", "middle" or "bottom". Optional, default is "top".
  • localized - 0 or 1. If 1 then the "str" actually contains a key used to fetch the value out of mxResources. Optional, default is 0, currently unused in diagrams.net.
  • vertical - 0 or 1. If 1 then the label is rendered vertically (rotated by 90 degrees). Optional, default is 0.
  • rotation - angle in degrees (0 to 360). The angle to rotate the text by. Optional, default is 0.
  • align-shape - 0 or 1. If 0 then the rotation of the shape is ignored when setting the text rotation. Optional, default is 1.
  • placeholders - 0 or 1. If 1 then placeholders of the form %name% will be replaced with their values. Optional, default is 0.

<image>

Image elements can either be external URLs, or data URIs, where supported (not supported in IE 7 or earlier versions).

Attributes are:

  • src - required string. Either a data URI or URL.
  • x,y - required decimals. The (x,y) position of the image.
  • w,h - required decimals. The width and height of the image.
  • flipH, flipV = optional 0 or 1. Used to flip the image along the horizontal/vertical axis. Default is 0 for both.

Sub-shapes

Note: This is only supported with the built-in shapes at diagrams.net.

<include-shape> allows sub-shapes to be rendered within the current shape by referencing the sub-shape by name.

Attributes are:

  • name - required string. The unique shape name.
  • x,y, and w,h -required decimals. The (x,y) position of the sub-shape and its width and height.

Example complex custom shape

A complex custom shape and its code, created in diagrams.net

This complex custom shape is represented by the following XML code. Copy and paste this XML into the Edit Shape dialog via Arrange > Insert > Shape in diagrams.net, then click Preview.

<shape aspect="variable" h="211" w="200" strokewidth="inherit">
    <connections>
         <constraint x="0.5" y="0" perimeter="0" name="N"/>
         <constraint x="0.5" y="1" perimeter="0" name="S"/>
         <constraint x="0" y="0.5" perimeter="0" name="W"/>
         <constraint x="1" y="0.5" perimeter="0" name="E"/>
         <constraint x="0" y="0" perimeter="0" name="NW"/>
         <constraint x="1" y="0" perimeter="0" name="NE"/>
         <constraint x="1" y="1" perimeter="0" name="SE"/>
         <constraint x="0" y="1" perimeter="0" name="SW"/>
    </connections>
    <background>
        <strokecolor color="#000000"/>
        <fillcolor color="#ffffff"/>
        <rect h="200" w="200" x="0" y="11"/>
    </background>
    <foreground>
        <fillstroke/>
        <save/>
        <save/>
        <save/>
        <save/>
        <save/>
        <save/>
        <save/>
        <dashpattern pattern="2 2"/>
        <dashed dashed="1"/>
        <rect h="150" w="150" x="25" y="36"/>
        <stroke/>
        <strokecolor color="#ff0000"/>
        <strokewidth width="4"/>
        <linejoin join="round"/>
        <linecap cap="round"/>
        <dashpattern pattern="5 5"/>
        <rect h="100" w="100" x="50" y="61"/>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <strokewidth width="5"/>
        <alpha alpha="0.25"/>
        <path>
            <move x="0" y="11"/>
            <line x="200" y="211"/>
        </path>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <dashpattern pattern="2 5"/>
        <dashed dashed="1"/>
        <path>
            <move x="200" y="11"/>
            <line x="0" y="211"/>
        </path>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <ellipse h="150" w="150" x="25" y="36"/>
        <stroke/>
        <fillcolor color="#66ff66"/>
        <alpha alpha="0.5"/>
        <ellipse h="100" w="100" x="50" y="61"/>
        <fillstroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <ellipse h="25" w="200" x="0" y="186"/>
        <stroke/>
        <ellipse h="200" w="25" x="0" y="11"/>
        <stroke/>
        <path>
            <move x="150" y="55"/>
            <line x="50" y="55"/>
            <line x="100" y="11"/>
            <close/>
        </path>
        <stroke/>
        <path>
            <move x="180" y="36"/>
            <line x="180" y="61"/>
        </path>
        <stroke/>
        <strokewidth width="2"/>
        <linecap cap="round"/>
        <path>
            <move x="185" y="36"/>
            <line x="185" y="111"/>
        </path>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <strokewidth width="3"/>
        <alpha alpha="0.5"/>
        <path>
            <move x="190" y="36"/>
            <line x="190" y="161"/>
        </path>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <strokewidth width="4"/>
        <dashpattern pattern="5 5"/>
        <dashed dashed="1"/>
        <path>
            <move x="195" y="36"/>
            <line x="195" y="186"/>
        </path>
        <stroke/>
        <restore/>
        <rect/>
        <stroke/>
        <strokecolor color="#000000"/>
        <fillcolor color="none"/>
        <path>
            <move x="26" y="22.75"/>
            <curve x1="26" x2="35.25" x3="41.5" y1="22.75" y2="0" y3="22.25"/>
            <curve x1="47.75" x2="55.25" x3="56.75" y1="44.5" y2="27.5" y3="20.25"/>
            <curve x1="58.25" x2="62.75" x3="75.75" y1="13" y2="21.5" y3="21"/>
            <curve x1="88.75" x2="83.5" x3="69.25" y1="20.5" y2="23.25" y3="30"/>
        </path>
        <stroke/>
        <path>
            <move x="122.5" y="21.5"/>
            <curve x1="130.25" x2="138.5" x3="138.25" y1="23.25" y2="10.5" y3="17.5"/>
            <curve x1="138" x2="156" x3="149.25" y1="24.5" y2="12.5" y3="17"/>
            <curve x1="142.5" x2="167.75" x3="163.75" y1="21.5" y2="24" y3="18.75"/>
            <curve x1="159.75" x2="180.75" x3="177" y1="13.5" y2="11.5" y3="14.25"/>
            <curve x1="173.25" x2="166.5" x3="172.75" y1="17" y2="30.5" y3="26.25"/>
            <curve x1="179" x2="178.5" x3="172.5" y1="22" y2="29.5" y3="31.25"/>
            <curve x1="166.5" x2="149.25" x3="151.5" y1="33" y2="35.25" y3="31.5"/>
        </path>
        <stroke/>
        <strokecolor color="#0033cc"/>
        <fillcolor color="#00ffff"/>
        <path>
            <move x="8" y="57"/>
            <line x="16.25" y="76"/>
            <line x="9.75" y="87.5"/>
            <line x="17" y="95.75"/>
            <line x="20" y="91"/>
            <line x="20.75" y="101.5"/>
            <line x="16.75" y="101"/>
            <line x="15.5" y="109.75"/>
            <line x="8.5" y="105"/>
            <line x="6.75" y="111"/>
            <line x="2.5" y="84"/>
            <line x="9.25" y="76.75"/>
            <close/>
        </path>
        <fillstroke/>
    </foreground>
</shape>