ereader_image Directory Reference

Directory dependency graph for ereader_image:

Directories
	inc
	src

Detailed Description

Decodes a baked RGB PNG cover through ra8_img_decode_blit(), nearest-neighbour scales it to fit a fixed RGB565 framebuffer in internal SRAM, and hashes the framebuffer (#106) – the same decode, scale and blit path the e-reader uses for cover art and in-chapter <img> figures. Allocation comes only from a fixed SRAM bump arena, so the decode reaches no malloc (NASA P10 Rule 3). Headless – no panel, SDRAM, touch or SD.

A fixed fixture, integer scale math and a fixed RGB565 pack make it deterministic, so the same hash appears on host, under the emulator and on silicon, and drift in the stb_image decoder, the scale math, the pack or the toolchain output trips it.

One non-obvious constraint this gate caught: stb_image otherwise compiles its global failure-reason and flag state as _Thread_local, and emulated TLS has no runtime on this bare-metal target, so the decode HardFaults mid-way. The single-TU build defines STBI_NO_THREAD_LOCALS to force plain statics.