mimg

Command-line image processing tool written in Zig.

Features

• Color adjustments, filters, effects, and geometric transforms
• Chain multiple modifiers in a single command
• PNG support via zigimg

Quick Start

# Apply a single modifier
zig build run -- input.png grayscale -o output.png

# Chain multiple modifiers
zig build run -- input.png brightness 20 saturation 1.3 sharpen -o output.png

# Complex pipeline
zig build run -- input.png exposure 0.5 vibrance 0.3 vignette 0.4 -o output.png

Available Modifiers

Color Adjustments

Modifier	Parameters	Description
brightness	<value>	Linear brightness adjustment (-255 to 255)
contrast	<factor>	Contrast adjustment (0.0 to 3.0)
saturation	<factor>	Saturation adjustment (0.0 to 3.0)
hue-shift	<degrees>	Rotate hue in color space (0 to 360)
gamma	<value>	Gamma correction (0.1 to 3.0)
exposure	<stops>	Exposure adjustment in stops (-2.0 to 2.0)
vibrance	<amount>	Enhance muted colors (0.0 to 1.0)
equalize	-	Histogram equalization for contrast

Color Effects

Modifier	Parameters	Description
grayscale	-	Luminance-based grayscale conversion
sepia	-	Apply sepia tone effect
invert	-	Invert all color channels
threshold	<value>	Binary threshold (0 to 255)
solarize	<threshold>	Solarization effect (0 to 255)
posterize	<levels>	Reduce color levels (2 to 16)
colorize	<r> <g> <b> <strength>	Tint with RGB color (0-255, strength 0.0-1.0)
duotone	<r1> <g1> <b1> <r2> <g2> <b2>	Map shadows to highlights gradient

Filters & Effects

Modifier	Parameters	Description
blur	<kernel>	Box blur (3, 5, 7, 9, etc.)
gaussian-blur	<sigma>	Gaussian blur (0.5 to 5.0)
sharpen	-	3×3 sharpen convolution
edge-detect	-	Sobel edge detection
emboss	-	3×3 emboss effect
median-filter	<size>	Median filter for noise (3, 5, 7)
noise	<amount>	Add random noise (0.0 to 1.0)
vignette	<strength>	Darken corners (0.0 to 1.0)
pixelate	<size>	Pixelation effect (2 to 50)
oil-painting	<radius>	Oil painting effect (1 to 5)

Geometric Transforms

Modifier	Parameters	Description
resize	<width> <height>	Nearest-neighbor resizing
crop	<x> <y> <width> <height>	Crop from top-left coordinate
rotate	<degrees>	Rotate clockwise (canvas auto-fits)
flip-horizontal	-	Flip image horizontally
flip-vertical	-	Flip image vertically

Global Options

Option	Shorthand	Description
--output <file>	-o	Output filename
--output-dir <dir>	-d	Output directory (auto-created)
--list-modifiers	-L	List all modifiers and exit
--verbose	-v	Enable verbose logging
--help	-h	Show help message

Usage Examples

Basic Operations

# Grayscale conversion
zig build run -- input.png grayscale -o output.png

# Resize to specific dimensions
zig build run -- input.png resize 800 600 -o output.png

# Crop region
zig build run -- input.png crop 50 50 300 300 -o output.png

# Rotate image
zig build run -- input.png rotate 45 -o output.png

Color Adjustments

# Brighten and increase saturation
zig build run -- input.png brightness 30 saturation 1.3 -o output.png

# Adjust contrast and gamma
zig build run -- input.png contrast 1.2 gamma 1.1 -o output.png

# Shift hue
zig build run -- input.png hue-shift 30 -o output.png

# Exposure and vibrance
zig build run -- input.png exposure 0.5 vibrance 0.4 -o output.png

Creative Effects

# Vintage look
zig build run -- input.png sepia vignette 0.4 -o output.png

# Artistic effect
zig build run -- input.png oil-painting 3 vibrance 0.3 -o output.png

# High contrast posterized
zig build run -- input.png posterize 8 contrast 1.3 -o output.png

# Duotone gradient
zig build run -- input.png duotone 75 30 120 255 220 100 -o output.png

Filter Chains

# Enhance details
zig build run -- input.png sharpen contrast 1.1 -o output.png

# Denoise and sharpen
zig build run -- input.png median-filter 3 sharpen -o output.png

# Blur and edge detect
zig build run -- input.png gaussian-blur 1.5 edge-detect -o output.png

Complex Pipelines

# Complete color correction
zig build run -- input.png exposure 0.3 contrast 1.1 saturation 1.2 vibrance 0.2 -o output.png

# Stylized output
zig build run -- input.png brightness 10 contrast 1.2 posterize 12 emboss -o output.png

# Geometric + color
zig build run -- input.png rotate 15 crop 100 100 400 400 brightness 20 saturation 1.3 -o output.png

Building

Requirements

• Zig 0.15.1 or later

Compile

zig build

The executable will be created in zig-out/bin/.

Run Tests

zig build test

Generate Gallery

zig build gallery

Generates visual examples in examples/gallery/gallery.md.

Installation

From Release

Download the latest binary from releases.

From Source

git clone https://github.com/brian-sinquin/mimg.git
cd mimg
zig build

Examples Gallery

Visual examples with sample outputs: examples/gallery/gallery.md

License

MIT License - see LICENSE file for details.