FramebufferScale

纯 C Linux framebuffer 虚拟化与缩放工具。应用继续使用指定的虚拟 framebuffer，适配层把画面输出到自动发现或明确指定的系统分辨率。

Pure C Linux framebuffer virtualization and scaling. The application keeps a required virtual framebuffer size while the adapter renders it to an automatically detected or explicitly selected system resolution.

功能 / Features

• /etc/framebufferscale.conf 配置，命令行参数覆盖配置。

• 虚拟分辨率必须明确，例如 1280x720。

• 系统分辨率支持 auto 或 1280x1024。

• fit 等比例居中与 stretch 全屏输出。

• LD_PRELOAD 适配库、C 启动器、无设备几何测试和 framebuffer 自测。

• Configuration from /etc/framebufferscale.conf, overridden by CLI options.

• A virtual size is required, for example 1280x720.

• System size can be auto or an explicit value such as 1280x1024.

• fit preserves aspect ratio; stretch fills the system framebuffer.

• Pure C preload library, launcher, geometry test, and framebuffer self-test.

构建 / Build

make
make check

在需要 GNU ABI 的目标上使用目标机或交叉工具链构建；项目不要求 Python、脚本运行时或额外服务。

Use the target or cross toolchain when a GNU ABI is required. The project does not require Python, a scripting runtime, or an external service.

车道启动 / Lane launch

在 Run.sh 中让启动器位于 emrc_main 之前：

./framebuffer-scale \
  --virtual-size 1280x720 \
  --system-size auto \
  --mode fit \
  -- ./emrc_main

--virtual-size 是必填项；--system-size auto 读取 /dev/fb0 的实际模式。长期运行时默认 seconds=0，进程退出时适配层自动清理；试验可使用 --seconds N。

Place the launcher before emrc_main in Run.sh. --virtual-size is required. --system-size auto reads the actual /dev/fb0 mode. The default lifetime is the application lifetime (seconds=0); use --seconds N for a bounded trial.

直接使用预加载库时，至少设置 SR_ATS_FB_PROGRAM、SR_ATS_FB_VIRTUAL_WIDTH 和 SR_ATS_FB_VIRTUAL_HEIGHT；其余参数可放在配置文件或环境变量中。

When using LD_PRELOAD directly, set at least SR_ATS_FB_PROGRAM, SR_ATS_FB_VIRTUAL_WIDTH, and SR_ATS_FB_VIRTUAL_HEIGHT. Other values may come from the configuration file or environment.

配置 / Configuration

复制 framebufferscale.conf.example 到 /etc/framebufferscale.conf，例如：

virtual_size=1280x720
system_size=auto
mode=fit
fps=15
seconds=0

配置文件缺少虚拟分辨率时，适配层拒绝初始化。明确指定 system_size 时，实际 framebuffer 分辨率必须匹配；auto 不做预设。

Copy framebufferscale.conf.example to /etc/framebufferscale.conf. Initialization is rejected when the virtual size is missing. An explicit system_size must match the actual framebuffer; auto discovers it at startup.

验证边界 / Validation boundary

make check 不打开真实 framebuffer。fb_scale_test 需要在已批准的 Linux 车道窗口运行，并应先确认备份、回滚和人工验收条件。

make check does not open a real framebuffer. fb_scale_test requires an approved Linux lane window with backup, rollback, and operator acceptance controls.

许可证 / License

MIT License。

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