Automate Your Build Pipeline with bmpPacker CLIAutomating image handling in a build pipeline saves time, reduces human error, and ensures consistent asset quality across environments. bmpPacker CLI is a lightweight command-line tool designed specifically for packing and optimizing BMP (bitmap) images used in games, embedded systems, and legacy applications that still rely on bitmap formats. This article explains why and how to integrate bmpPacker into modern CI/CD workflows, offers practical examples, and provides tips to maximize performance and reliability.
Why automate BMP processing?
Many projects still use BMP files for specific reasons: predictable, uncompressed pixel layouts, easy decoding on constrained devices, or tooling compatibility. Manual processing of BMP assets during development leads to:
- Inconsistent compression/packing settings.
- Risk of shipping non-optimized or incorrectly formatted assets.
- Time spent by developers performing repetitive tasks.
Automation eliminates these problems by making image packing part of the reproducible build. Once configured, every commit or release will run the same steps to prepare assets, ensuring consistent output across machines and environments.
What bmpPacker CLI provides
bmpPacker CLI focuses on packing and optimizing BMP files with features useful in automated workflows:
- Command-line interface for scripting and CI usage.
- Batch processing of directories and recursive file handling.
- Options to control compression, palette generation, and output layout.
- Deterministic output to avoid unnecessary diffs in builds.
- Lightweight and fast, suitable for CI runners with limited resources.
Below are common cli-like options found in packing tools (example flags — adapt to your bmpPacker version):
- –input, -i: input file or directory
- –output, -o: output directory or file
- –recursive, -r: process directories recursively
- –compress-level, -c: compression/packing level (0–9)
- –palette, -p: force palette generation (for 8-bit/4-bit BMPs)
- –overwrite: overwrite existing outputs
- –verbose: verbose logging for debugging
Integrating bmpPacker into local builds
Start by adding a script to your project’s build tooling to run bmpPacker as part of asset preparation. For example, in an npm-based project you can add an npm script in package.json:
{ "scripts": { "pack-bmp": "bmpPacker --input assets/raw_bmp --output assets/packed_bmp --recursive --compress-level 7" } } Then call the script from your main build step:
{ "scripts": { "build": "npm run pack-bmp && webpack --config webpack.prod.js" } } For Makefile-based projects:
ASSET_SRC := assets/raw_bmp ASSET_OUT := assets/packed_bmp .PHONY: pack-assets pack-assets: bmpPacker -i $(ASSET_SRC) -o $(ASSET_OUT) -r -c 7 build: pack-assets # other build steps here This ensures packed BMPs are generated before compilation or packaging steps that use them.
Using bmpPacker in CI/CD (GitHub Actions example)
Embedding bmpPacker into CI makes sure every branch and pull request has properly packed BMPs. Here’s a minimal GitHub Actions workflow:
name: CI on: push: branches: [ main ] pull_request: jobs: build: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 - name: Install bmpPacker run: | sudo apt-get update sudo apt-get install -y bmpPacker - name: Pack BMPs run: bmpPacker -i assets/raw_bmp -o assets/packed_bmp -r -c 7 - name: Build project run: make build - name: Upload packed assets (artifact) uses: actions/upload-artifact@v4 with: name: packed-bmp path: assets/packed_bmp If bmpPacker is distributed as a binary release or npm package, change the install step accordingly (download a release, curl + tar, or npm install).
Verifying outputs and enforcing policies
Automated pipelines should validate outputs to prevent regressions:
- Size checks: fail the build if packed files exceed expected sizes.
- CRC/hash checks: ensure deterministic output by comparing generated hashes against previously known-good values.
- Linting: run an image linter to verify color depth, dimensions, or palette constraints.
Example shell check:
EXPECTED_SIZE=102400 ACTUAL_SIZE=$(du -b assets/packed_bmp/sprite.bmp | cut -f1) if [ "$ACTUAL_SIZE" -gt "$EXPECTED_SIZE" ]; then echo "Packed sprite.bmp too large ($ACTUAL_SIZE bytes)" exit 1 fi Parallelization and performance
Large asset sets benefit from parallel processing. Run multiple bmpPacker instances in parallel, partitioning by subdirectories or file lists.
GNU parallel example:
find assets/raw_bmp -name '*.bmp' | parallel -j8 'bmpPacker -i {} -o assets/packed_bmp/{/.} -c 7' Be mindful of CI runner CPU/RAM limits; adjust -j accordingly.
Caching and incremental builds
To speed up CI and local builds:
- Cache packed output between runs when source images haven’t changed.
- Use file timestamps or hashes to skip packing unchanged files.
Basic incremental script:
for f in $(find assets/raw_bmp -name '*.bmp'); do out="assets/packed_bmp/$(basename "$f")" if [ ! -f "$out" ] || [ "$f" -nt "$out" ]; then bmpPacker -i "$f" -o "$out" -c 7 fi done Combine this with CI caching (e.g., actions/cache) to speed up repeated workflows.
Error handling and logging
- Fail-fast behavior: let the pipeline stop on bmpPacker non-zero exits to prevent bad assets from being used.
- Verbose logs for debugging: enable –verbose on CI for failing runs.
- Artifacts for debugging: upload packed outputs and logs for failed jobs.
Example advanced pipeline (build → test → release)
- pack assets (bmpPacker)
- build application/binary
- run unit/integration tests (including tests that load packed BMPs)
- run regressions (image comparison tests)
- if all green, create release artifact including packed BMPs
This sequence ensures assets are part of the same reproducible artifact tested before release.
Tips and best practices
- Keep bmpPacker configuration in source control (config file or well-documented CLI flags).
- Make outputs deterministic: fixed palette generation, stable ordering of files.
- Test on CI runner similar to production environment (same OS, architecture).
- Use size and integrity checks as gating rules for merges/releases.
- Document the pipeline step for contributors so they can run asset packing locally.
Troubleshooting common issues
- Permission errors: ensure CI runner has write permission to output directories.
- Non-deterministic outputs: enforce deterministic settings or sort inputs before packing.
- Performance bottlenecks: partition work and increase parallelism; use caching.
- Missing binary: install bmpPacker in the CI image or include it in repo tools.
Conclusion
Automating BMP packing with bmpPacker CLI brings consistency, speed, and reliability to build pipelines that rely on bitmap assets. Integrate bmpPacker early in your build steps, validate outputs with checks and tests, and use caching and parallelism to keep CI times low. With these practices, your builds will be less error-prone and more reproducible, letting developers focus on features rather than asset wrangling.
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