Public evidence

apps.bar-graph

Machine-checked verification for runtime version 2.1.0.

Verification

13/13 runtime tests

Golden tests 8 / 8
Boundary tests 5 / 5
Published UI cases 2 documented
Runtime tested Yes
Source checked Yes
Browsers Designed for modern browsers

Fingerprint sha256:e5984c3a1a3aafcc7bdbb4c52bc9af015f8a68bce71e656ff81d401279e4b533

Designed for modern Chrome, Edge, Firefox, and Safari. No version-locked browser matrix is published yet.

PNG export (image/png, bar-graph.png) and on-canvas tick labels are published page cases — not a pixel-level canvas attestation.

Build & scope

Engine identity and declared limitations.

Tool: bar-graph
Engine: bar-graph-runtime
Engine build: —
Evidence core: 2026-08-19T22:32:15.117Z
Rendered: 2026-08-19T22:32:15.117Z
Last reviewed: 2026-08-20

Assumptions

Scale domain is [min(0, min(values)), max(0, max(values))].
Positive bars grow away from the zero baseline toward domainMax; negative bars toward domainMin.
If every value is 0, domain is [0, 1] and all bars have length 0.

Limitations

One series per chart. Malformed lines are skipped.
Axis labels longer than about 8–10 characters are truncated on the canvas.
PNG export is a local canvas snapshot, not a server-rendered image.

Sources

Standards and references supporting this runtime specification. Methods are listed separately — they are algorithms, not bibliographic sources.

Vega-Lite — Bar Chart with Negative Values and a Zero-Baseline
Supports: Negative bars cross a zero baseline in the opposite direction
Vega-Lite — Scale
Supports: Quantitative bar scale includes zero unless explicitly disabled

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`tc01-normal-positive`	golden	pass	Expected max=20 · min=10 · aLength=0.5 · bLength=1 · Actual summary=Count 2 · Max 20 · Min 10 · Avg 15.0
`tc02-single-value`	golden	pass	Expected Single full-length bar · Actual lengthFrac=1 · max=10
`tc03-decimal`	golden	pass	Expected aLength=0.5454545454545454 · bLength=1 · Actual {"lengths":[0.5454545454545454,1]}
`tc04-zero-mixed`	boundary	pass	Expected aLength=0 · bLength=1 · Actual {"lengths":[0,1],"signs":[0,1]}
`tc05-all-zero`	boundary	pass	Expected max=0 · min=0 · avg=0 · noNaN=true · Actual finite=true
`tc06-negative-only`	golden	pass	Expected grow=down · bLonger=true · Actual {"scale":{"min":-20,"max":0},"lengths":[0.5,1],"grow":["down","down"]}
`tc07-mixed-signed`	golden	pass	Expected aGrow=down · bGrow=up · notEqualLength=true · Actual {"scale":{"min":-10,"max":20,"zeroFrac":0.3333333333333333},"lengths":[0.3333333333333333,0.6666666666666667],"grow":["down","up"]}
`tc08-horizontal-signed`	golden	pass	Expected equalLength=true · Actual {"lengths":[0.5,0.5],"vertical":["up","down"],"horizontal":["right","left"]}
`tc08b-axis-captions`	golden	pass	Expected customPreserved=true · Actual {"v":{"xLabel":"Category","yLabel":"Value"},"h":{"xLabel":"Value","yLabel":"Category"},"swapped":{"xLabel":"Value","yLabel":"Category"},"custom":{"xLabel":"Month","yLabel":"USD"}}
`tc09-malformed-line`	boundary	pass	Expected {"pairs":[{"label":"B","value":10}]}
`tc10-empty`	boundary	pass	Expected count=0 · Actual count=0
`tc11-large-value`	boundary	pass	Expected finite=true · lengthFrac=1 · Actual value=1e+308 · max=1e+308 · lengthFrac=1
`tc12-sample-summary-ticks`	golden	pass	Expected summary=Count 6 · Max 22 · Min 8 · Avg 15.7 · Actual summary=Count 6 · Max 22 · Min 8 · Avg 15.7