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This page describes breaking API changes between diagrams 1.1 and 1.2, along with explanations of how to migrate to the new 1.2 API.

Attributes using Measure

Many distances are now specified using values of type Measure. See the user manual for full details. The most noticeable effects of this change in porting diagrams code to 1.2 will be type errors on uses of attribute functions like lw, dashing, and fontSize.

  • To simply retain the existing behavior, replace lw with lwG, dashing with dashingG, and fontSize with fontSizeL.
  • In many cases, you can simply remove calls to lw, since the default behavior is much more sensible. You can also use the named line weights provided in Diagrams.TwoD.Attributes: none, ultraThin, veryThin, thin, medium, thick, veryThick, or ultraThick. For example, replace lw 0 with lw none, and replace (say) lw 0.2 with lw veryThick (though note that the relationship between the number used previously and the proper choice of line weight depends on the context, because the old semantics was not very sensible).
  • While we think the new default line weight will work for more people more of the time, diagrams which used the old default will compile without error and may render quite differently. You can express the old default as lwG 0.01, or add lw with the named line weights as necessary.

Removal of freeze

The freeze function has been removed. Most users probably were not using it; if you were, you have several options for replacing it, depending on how you were using it:

  • If you were just using it to get some lines to scale along with a diagram, use a Local line width (e.g. ... # lw (Local 2) or ... # lwL 2).
  • The above will not work if you were doing non-uniform scaling and really care that the lines should come out looking squished and stretched. In that case, use functions in Diagrams.TwoD.Offset to create a path corresponding to the stroked line, and then fill and transform it normally.


Head and tail size

The size of arrow heads and tails is now specified in terms of length instead of the radius of their circumcircle. In addition, the lengths are specified using Measure. For convenience, aliases tiny, verySmall, small, normal, large, veryLarge, and huge have been provided. For example,

... & headSize .~ 0.7

might be replaced with

... & headLength .~ large


Gaps at the ends of arrows are also specified using Measure R2. Also, the gap traversal has been replaced by gaps for consistency in naming, though gap is still provided for backwards compatibility. For example, replace

... & gap .~ 1


... & gaps .~ Local 1

Head and tail color

The lenses headColor and tailColor have been replaced by headTexture and tailTexture. These can now handle more general textures, e.g. gradients. To get a solid color, use the solid function, e.g. replace

... & headColor blue


... & headTexture (solid blue)


If you were using the cairo backend to include PNG images in your diagrams then you will need to make some small changes to your code using the new Image API. Diagrams now distinguishes between external and embedded images, cairo (as it has done in previous versions) only supports external images. For example if you were creating a diagram from a PNG called "myImage.png" using

image "~/myImage.png" 1 1

then you can replace it with

image (uncheckedImageRef "~/myImage.png" 1 1)

and get exactly the same behavior as with 1.1. Additionally, you can now create a "checked" external image with the function loadImageExt which will utilize the Juicy Pixels library to make sure the image exists and calculate its dimension so you don't need to provide a width and height. See the user manual for full details


These changes will not affect most users, but are listed here for completeness.

  • The avgScale function has been moved from Diagrams.TwoD.Transform to Diagrams.Core.Transform.
  • Most 2D attributes have been moved from Diagrams.Attributes to Diagrams.TwoD.Attributes.
  • The Angle definition and related functions have moved to a separate module, Diagrams.Angle.