bug(mat-button, mat-icon): mat-icon inside of mat-button are truncated

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

Not sure which

Description

Using Angular 19 with angular material, if I put a mat-icon element inside of a mat-button, the icon is not completely visible. It is truncated a little at its top and bottom. See reproduction StackBlitz below.

Reproduction

Forked the "Button Angular Component" example to display the problem.

Editor: https://stackblitz.com/edit/3zsvfedr?file=src%2Fexample%2Fbutton-overview-example.html
Application: https://3zsvfedr.stackblitz.io

See the second button in the "Basic" "Raised" "Stroke" and "Flat" table rows.

Expected Behavior

I would expect the icon to be fully visible, not truncated. In case of the add_circle icon, I would expect its shape to be perfectly round.

Actual Behavior

The top and bottom of the icon are truncated (cropped) which makes it painfully not round.

Environment

• Angular: 19
• CDK/Material: 19.2.7
• Browser(s): Edge, Chrome and Firefox
• Operating System: Windows

Start with the linked StackBlitz reproduction and compare the second buttons in the Basic, Raised, Stroke, and Flat examples. Trace the Angular Material mat-button and mat-icon rendering and styling involved in the clipping. Done means the icon is fully visible and the add_circle icon appears round across the reported browsers.