painter: the built-in font can be magnified

[tannevaled]

The font is 5×7 pixels and was drawn at that size whatever the display. On a screen with two device pixels to the point a glyph is three and a half points tall — not small type, type nobody can read. Every other metric in the toolkit above this passes through a HiDPI scale; the one thing a person actually reads did not.

• a whole number, because a bitmap font magnified by 1.5 has rows of unequal thickness and reads worse than the size it came from;
• below 1 is 1: an invisible line of text is not a size anybody asked for;
• TextWidth and TextHeight come with it — measuring was arithmetic every caller did for itself with the advance hard-coded, a number that has just stopped being constant, so every one of them would have right-aligned into the wrong place;
• the zero value is 1:1, so nothing that exists changes.

The test checks the magnification exactly: one lit bit becomes an n×n block, so a scale of three lights nine times the ink for the same glyphs.

🤖 Generated with Claude Code