diffimg: binary tool for comparing images (#9668)

This tool uses existing libraries: image, imageio, imageio-lite,
imagediff to perform difference comparison for on-disk images.

We refactor renderdiff to use this tool instead of using
python dependencies.


Co-authored-by: Ben Doherty <bendoherty@google.com>

.github/workflows/postsubmit-main.yml

@@ -16,8 +16,8 @@ jobs:
       - uses: ./.github/actions/linux-prereq
       - id: get_commit_msg
         uses: ./.github/actions/get-commit-msg
-      - name: Prerequisites
-        run: pip install tifffile numpy
+      - name: Build diffimg
+        run: ./build.sh release diffimg
       - name: Run update script
         env:
           GH_TOKEN: ${{ secrets.FILAMENTBOT_TOKEN }}

.github/workflows/presubmit.yml

@@ -125,7 +125,6 @@ jobs:
         uses: ./.github/actions/get-commit-msg
       - name: Prerequisites
         run: |
-          pip install tifffile numpy
           # Must have at least clang-16 for a webgpu/dawn build.
           sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
         shell: bash
@@ -139,6 +138,9 @@ jobs:
           set -eux
           GOLDEN_BRANCH=$(echo "${COMMIT_MESSAGE}" | python3 ${TEST_DIR}/src/commit_msg.py)
           bash ${TEST_DIR}/generate.sh
+          # Build diffimg tool
+          ./build.sh release diffimg
+
           python3 ${TEST_DIR}/src/golden_manager.py \
                   --branch=${GOLDEN_BRANCH} \
                   --output=${GOLDEN_OUTPUT_DIR}
@@ -149,7 +151,9 @@ jobs:
           python3 ${TEST_DIR}/src/compare.py \
               --src=${GOLDEN_OUTPUT_DIR} \
               --dest=${RENDER_OUTPUT_DIR} \
-              --out=${DIFF_OUTPUT_DIR} 2>&1 | tee compare_output.txt
+              --out=${DIFF_OUTPUT_DIR} \
+              --diffimg="$(pwd)/out/cmake-release/tools/diffimg/diffimg" \
+              --test="${TEST_DIR}/tests/presubmit.json" 2>&1 | tee compare_output.txt
 
           if grep "Failed" compare_output.txt > /dev/null; then
              DELIMITER="EOF_FILE_CONTENT_$(date +%s)" # Using timestamp to make it more unique