[FEATURE] Add CLI options to customize font and icon sizes

[XedinUnknown]

Summary

Would be useful to have CLI options like --fontsize and --iconsize to control the size of text labels and resource icons in generated diagrams.

Current Behavior

Currently, font size (18px) and icon sizes (46px) are hardcoded in the internal Graphviz generation. Users cannot customize these without post-processing the output.

Use Case

Different diagrams have different readability requirements - larger diagrams with many resources benefit from bigger fonts/icons for better readability.

Suggested Options

--fontsize INT    Font size for resource labels (default: 18)
--iconsize INT     Icon size in pixels (default: 46)

Alternative

If annotations can already control this, please point me to the documentation - I couldn't find it.

Additional Context

This would also help with the HTML visualise output where the icons and text can appear small.

[patrickchugh]

This is a good idea @XedinUnknown I will work on this shortly.

Do you think it is better to put this in the terravision.yml annotations file or as a CLI option? Not sure if everyone wants to type in --fontsize every time vs having it as a default in YAML?

[XedinUnknown]

@patrickchugh, thanks for replying!
In my ideal world, all CLI options would be reflected in the config, and vice-versa. But if I had to choose, I'd side with what you wrote: it's probably parameters that people would want to have consistently across builds.

On the other hand, in case of automations - nobody really cares whether to write it in the Terravision config or in a GH workflow. And personally, when I adopt a tool like yours into a project - it is reflected in a changeset that updates the Makefile with a target that encodes all the CLI args etc. And if you do it only in YAML, that is much harder to script or otherwise make dynamic. yq is easy to use, but it still requires an extra step that updates checked out files, which adds complexity to automations. The point being that anyone who uses your tool today is likely writing an automation or asking AI to use your tool for them (or both, which is what I did), so keeping it machine-friendly is kinda important.

So, I'm torn 😓 I humbly acknowledge that the decision is entirely up to you, confident that you'll make the best choice based also on the above points of view which you have so kindly requested 🙏

[patrickchugh]

Hi @XedinUnknown I had a rethink about this and realised the icons and text were too small overall by default, and so v0.40 bumps the sizes of all icons and text to be larger. Can you try out the latest version and tell me if we still need a fontsize bump option?

[XedinUnknown]

@patrickchugh, they look a bit bigger, thank you! But the text is still very small. That's why ideally, there would be a way to controll these things from outside.

[XedinUnknown]

Actually, even if you do that, I still need to patch the HTML eventually: the Connected Resources section in the sidebar takes the whole height of the sidebar if there's enough content, and cannot be resized. My current approach - is to run a small script patch-diagram:

#!/usr/bin/env python3
"""Post-process a terravision HTML diagram with local fixes."""
import sys

if len(sys.argv) != 2:
    sys.exit(f"Usage: {sys.argv[0]} <html-file>")

with open(sys.argv[1]) as f:
    html = f.read()

# Constrain related-section panel height so it doesn't cover tab content
html = html.replace(
    '</body>',
    '<style>.related-section{max-height:250px;overflow:auto}</style></body>'
)

with open(sys.argv[1], 'w') as f:
    f.write(html)

Of course, this isn't ideal, and I'd much prefer editing a template.

In fact, here's my process that generates my diagram on CI:

SOURCE     := ./dev
PLANFILE   := $(SOURCE)/terravision.plan.json
GRAPHFILE  := $(SOURCE)/terravision.graph.dot
TF_SOURCES := $(wildcard $(SOURCE)/*.tf $(SOURCE)/*.tfvars $(SOURCE)/*.tftest.hcl modules/**/*.tf)
OUTFILE    := $(SOURCE)/architecture
CI         ?=

# When CI is set (e.g. on GitHub Actions where CI=true), all work is done in-place:
# plan files and diagram outputs are written directly to SOURCE. This is safe because
# CI workspaces are disposable, and leaves all artifacts available for inspection.
# Without CI, all intermediate work is done in a mirror of the project under /tmp
# to avoid polluting the local workspace.
ifdef CI
  WORKDIR    := $(CURDIR)
  _PLANFILE  := $(PLANFILE)
  _GRAPHFILE := $(GRAPHFILE)
  _OUTFILE   := $(OUTFILE)
else
  WORKDIR    := /tmp$(CURDIR)
  _PLANFILE  := $(WORKDIR)/$(PLANFILE)
  _GRAPHFILE := $(WORKDIR)/$(GRAPHFILE)
  _OUTFILE   := $(WORKDIR)/$(OUTFILE)
endif

.PHONY: help
help: ## Show available targets. Set CI=1 to run in-place (CI environments skip temp dir isolation).
	@grep -E '^[a-zA-Z_-]+:.*##' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*##"}; {printf "  %-20s %s\n", $$1, $$2}'

$(_PLANFILE) $(_GRAPHFILE): $(TF_SOURCES)
ifdef CI
	cd $(SOURCE) && $(CURDIR)/bin/mocktfplan -p $(CURDIR)/$(_PLANFILE) -g $(CURDIR)/$(_GRAPHFILE)
else
	cp -r . $(WORKDIR)/
	rm -rf $(WORKDIR)/$(SOURCE)/.terraform $(WORKDIR)/$(SOURCE)/.terraform.lock.hcl
	cd $(WORKDIR)/$(SOURCE) && $(CURDIR)/bin/mocktfplan -p $(_PLANFILE) -g $(_GRAPHFILE)
endif

.PHONY: tfv-plan
tfv-plan: $(_PLANFILE) $(_GRAPHFILE) ## Generate plan snapshot if TF sources changed (no AWS credentials needed).

.PHONY: tfv-visualise
tfv-visualise: $(_PLANFILE) $(_GRAPHFILE) ## Generate interactive HTML diagram from the plan snapshot.
	terravision visualise \
		--source $(SOURCE) \
		--planfile $(_PLANFILE) \
		--graphfile $(_GRAPHFILE) \
		--outfile $(_OUTFILE)
	test -s $(_OUTFILE)-aws.html
	$(CURDIR)/bin/patch-diagram $(_OUTFILE)-aws.html
ifndef CI
	cp $(_OUTFILE)-aws.html $(OUTFILE)-aws.html
endif

.PHONY: tfv-draw
tfv-draw: $(_PLANFILE) $(_GRAPHFILE) ## Generate PNG diagram from the plan snapshot.
	terravision draw \
		--source $(SOURCE) \
		--planfile $(_PLANFILE) \
		--graphfile $(_GRAPHFILE) \
		--outfile $(_OUTFILE)
	test -s $(_OUTFILE)-aws.dot.png
ifndef CI
	cp $(_OUTFILE)-aws.dot.png $(OUTFILE)-aws.png
endif

.PHONY: tfv-clean
tfv-clean: ## Remove generated diagram and plan snapshot files.
	rm -f $(PLANFILE) $(GRAPHFILE)
	rm -f $(OUTFILE)-aws.html $(OUTFILE)-aws.png $(OUTFILE)-aws.dot

[patrickchugh]

Hi @XedinUnknown, this is addressed in v0.41.0. You can now use:

terravision draw --source ./infra --fontsize 50 --iconsize 200
Both flags work across all output formats (PNG, SVG, PDF, draw.io, HTML visualiser). Node spacing and cluster margins scale automatically so labels don't overflow boundaries.

You can also set defaults in your terravision.yml so you don't have to pass the flags every time:

format: 0.3
fontsize: 40
iconsize: 180
CLI flags take precedence over the YAML values. We also fixed the sidebar .related-section covering content in the HTML visualiser as you mentioned.

Could you give it a try and let us know if it works for your use case?

[patrickchugh]

@XedinUnknown Closing due to no response. Let me know if this needs to re-open again. Thanks for the valuable feedback.