Fit or stretch background images within the map canvas

[alcatron]

Selecting a background previously changed the canvas to the image dimensions. Add Fit, Stretch and original Image size choices to Map Properties, persisted as a background_sizing hint.

Fit centers the image within the current canvas while preserving proportions; Stretch fills the canvas. Image size preserves existing behavior. Missing or invalid hints use Image size for compatibility. PHP locals follow snake_case conventions.

Validation: 226 PHP 8.3 tests passed in an isolated fixture layout. A real-engine regression saves each mode through setMapProperties(), reloads it, renders the image and checks canvas dimensions and pixels. It also checks invalid editor input preserves the existing hint and invalid stored hints use the renderer fallback. Syntax, whitespace and manifest checks passed; measured changed-line coverage is 100%, with existing editor entry/action exemptions. Full running-installation integration remains unverified for this revision.

Further review follow-up

Addressed in 2824a1e. Moved background_sizing lookup and validation after the post-processing loop. Added actual engine rendering checks for post-processor overrides to fit, stretch, image and an invalid value, verifying canvas dimensions and background pixels. All 226 plugin tests pass (5437 assertions); measured changed-line coverage passes at 19/19.

[Copilot]

🟡 Changes recommended

The new files and variables violate repository standards, and the editor persistence path lacks direct coverage.

5 open findings

• Rename renderer locals to snake_case · New
• Use snake_case for the new variable · New
• Replace MIT header with the standard GPL-v2 header · New
• Use the repository-standard GPL-v2 header · New
• Rename local variable to snake_case · New

What changed in this PR

Adds configurable background-image sizing while preserving backward-compatible behavior.

Changes:

• Adds Fit, Stretch, and Image size editor options.
• Persists sizing as a map hint and applies it during rendering.
• Adds rendering regression coverage and translations.

File	Description
weathermap-cacti-plugin-editor.php	Adds the sizing selector.
lib/​editor.actions.php	Saves the selected mode.
lib/​WeatherMap.class.php	Implements background scaling and centering.
tests/​Unit/​BackgroundSizingEngineTest.php	Runs the isolated regression test.
tests/​Support/​BackgroundSizingEngineRegression.php	Tests persistence and rendered dimensions.
locales/​po/​cacti.pot	Adds translated UI strings.
CHANGELOG.md	Documents the feature.

🧠 Review effort: Balanced

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[Copilot]

🔵 Needs a closer look

The fit-mode regression test can pass even when the fitted image is never rendered.

0 open findings

5 resolved since last review

• Rename local variable to snake_case
• Use the repository-standard GPL-v2 header
• Replace MIT header with the standard GPL-v2 header
• Use snake_case for the new variable
• Rename renderer locals to snake_case

Previously missed (1)

In code that hasn't changed since last review

Assert fitted image pixels are rendered, not just padding

tests/​Support/​BackgroundSizingEngineRegression.php:85

The fit-mode assertion only proves that the letterbox pixel is not red. A regression that never copies the fitted image would still pass, because the canvas background also satisfies this condition. Please also assert that a pixel inside the expected fitted area is red so the test verifies the image was rendered, not merely that padding exists.

🧠 Review effort: Balanced

[Copilot]

🟢 Approval recommended

The implementation preserves compatibility, validates inputs, and includes focused end-to-end regression coverage.

0 open findings

🧠 Review effort: Balanced

[Copilot]

🟡 Changes recommended

Background sizing is read before post-processors, so their hint updates cannot affect rendering.

1 open finding

• Read background_sizing after post-processing plugins run · New

🧠 Review effort: Balanced

[Copilot]

🟢 Approval recommended

The implementation matches the stated behavior and includes focused regression coverage for all modes and fallbacks.

0 open findings

1 resolved since last review

• Read background_sizing after post-processing plugins run

🧠 Review effort: Balanced

[Copilot]

🟡 Changes recommended

The regression fixture defines a Cacti core helper locally instead of using the shared configurable test bootstrap.

1 open finding

• Move conditional Cacti helper stub to unit test bootstrap · New

🧠 Review effort: Balanced