# test_image_cli

A development tool for generating test images and writing them to PPM files. Used to verify the `test_image` module's pattern generators and pixel format output without needing a camera or display.

---

## Build

From the repository root:

```sh
make cli
```

The binary is placed in `build/cli/`.

---

## Usage

```sh
./test_image_cli [--pattern bars|ramp|grid]
                 [--width N] [--height N]
                 [--format yuv420|yuv422|bgra]
                 --out FILE.ppm
```

All options are optional except `--out`.

| Option | Default | Description |
|---|---|---|
| `--pattern` | `bars` | Test pattern to generate |
| `--width N` | `1280` | Image width in pixels |
| `--height N` | `720` | Image height in pixels |
| `--format` | `yuv420` | Internal pixel format before PPM conversion |
| `--out FILE` | required | Output file path |

### Patterns

| Name | Description |
|---|---|
| `bars` | Colour bars (SMPTE-style) |
| `ramp` | Luminance ramp from black to white |
| `grid` | Crosshatch grid |

### Formats

| Name | Description |
|---|---|
| `yuv420` | Planar YUV 4:2:0 |
| `yuv422` | Packed YUV 4:2:2 |
| `bgra` | Packed BGRA 8-bit |

The output is always written as a PPM (RGB) file regardless of format; the internal format affects how the pattern is generated and converted.

### Example

```sh
./test_image_cli --pattern bars --width 1920 --height 1080 --format yuv420 --out bars.ppm
```

Open with any image viewer that supports PPM (e.g. `feh`, `eog`, GIMP).

---

## Relationship to the Video Routing System

`test_image_cli` exercises the `test_image` module used by development tools to inject synthetic frames without a camera. The same module drives the xorg test pattern display in `xorg_cli`.

See also: [`xorg_cli.md`](xorg_cli.md) for live window rendering.