Compositing and Blending Level 1 (Compositing 1) Implementation Report


This report was prepared to document the current implementation status of the Compositing and Blending Level 1 (Compositing 1) specification as of 6 July 2023 and is based on current test results available in the W3C Conformance Test Harness.


Sixteen user agents, built from nine rendering implementations, were tested across five operating systems.


The 6 July 2023 revision of the Compositing 1 test suite was used. The test suite consists of 65 tests.

These tests are available in several host language variants:

Some tests only apply to certain language variants; the results for each tested implementation are reported for each tested language variant. Also, not all tests are applicable to each implementation; for example, a browser which implements HTML but not XHTML is not tested for XHTML.


In summary, the results show that all 65 tests were passed by at least two of the tested implementations.

Results were gathered from implementation reports submitted by user agent vendors as well as the general public via the W3C Conformance Test Harness.