Resumed to project. INIT

notes/04-text_renderer.md

@@ -0,0 +1,31 @@
+# Text Renderer
+
+## Current state
+
+No text rendering exists yet. No font loading or glyph blitting code exists.
+
+## Goal
+
+Draw ASCII text into the `u8` framebuffer using a bitmap font, respecting the palette-index
+color model (one u8 per pixel, no RGBA).
+
+## Design notes
+
+- A bitmap font is the right fit: each glyph is a small tile of palette indices, blitted
+  directly into the framebuffer using the existing blit primitive in `pixelhelper.rs`.
+- Likely approach: a fixed 8×8 or similar glyph grid packed into a TGA or raw binary,
+  one glyph per ASCII codepoint starting at 0x20 (space).
+- The font image itself should be indexed: foreground pixels carry a nonzero palette index
+  (caller supplies the color), background pixels are index 0 (transparent/skip).
+- API sketch:
+  ```rust
+  fn draw_text(frame: &mut [u8], font: &Font, x: i32, y: i32, color: u8, text: &str);
+  ```
+- `Font` holds the glyph sheet as an `Image` plus glyph width/height.
+
+## Open questions
+
+- How do we handle proportional spacing of different characters?
+- How do we store font data in memory?
+- How do we handle font color rendering?
+- How do we handle special characters like Ä, Ö, Ü, ß, etc.?