Andrew Kesterson
16b38c1138
Chapters 6 and 8 described what a verb draws in prose. Eight figures now show it, and each one is produced by running the BASIC listing printed immediately above it -- so a picture cannot drift away from the code beside it, which is the way a screenshot goes wrong and the way nothing notices. tools/screenshot.c is a second SDL host, much smaller than the frontend: dummy video driver, software renderer, run to completion, read the target back, write a PNG. It draws no text layer on purpose, so a READY in the corner is not noise in a figure about BOX and no font has to be resolved. tools/docs_screenshots.sh reads the new screenshot=NAME fence tag straight out of the markdown. size=WxH is the second tag, and SCALE's figure uses it: the point being made is a 320x200 listing filling a larger window, which cannot be made on a 320x200 surface. Two gates, answering different questions. docs_examples fails a tagged block with no image, in both configurations, so a figure cannot be added and forgotten. docs_screenshots -- a CTest, AKGL build only -- re-renders every figure and compares byte for byte, so a listing edited without regenerating fails. Only the second catches a stale picture. The PNGs are checked in because a reader on the forge has no build tree, and docs/images/README.md says loudly that they are generated. Regenerating is never part of a build: the target is run deliberately, so a make cannot put eight binary diffs in front of whoever ran it. Drawing the BOX figure caught a defect in TODO.md itself. Deviation 16 claimed in bold that BOX fills on a negative angle while its own paragraph said the fill was filed rather than implemented. BOX cannot fill, and filled_rect is reached by no verb as a result. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Generated figures — do not edit
Every PNG in this directory is output, not an asset. Each one is produced by running
the BASIC listing shown immediately above it in the chapter, through
tools/screenshot.c, and it is checked in only because a reader on the forge has no
build tree to generate it from.
To change a picture, change the listing and regenerate:
cmake --build build-akgl --target docs_screenshots
Editing a PNG here by hand puts the picture out of step with the code it illustrates,
which is the exact failure this arrangement exists to prevent — and the docs_screenshots
test will fail on it, because it re-renders every figure and compares byte for byte.
The tag that ties a figure to its listing is screenshot=NAME in the fence info string,
and MAINTENANCE.md documents it along with size=WxH for a figure that needs a surface
other than 320 by 200. A tagged block with no image here fails docs_examples in both
build configurations, so a figure cannot be added to a chapter and then forgotten.