bimg Go Package

To install the bimg Go package, use the following command:

go get -u github.com/h2non/bimg

libvips Prerequisites

bimg requires libvips to be installed on your system. It is recommended to use version 8.8 or higher.

Follow the official installation instructions for your platform: https://libvips.github.io/libvips/install.html

Note on format support:

• libvips 8.3+ is required for GIF, PDF, and SVG support.
• libvips 8.9+ is required for AVIF support (requires libheif with an AVIF en-/decoder).

To debug issues with bimg or the underlying libvips library:

1. Enable bimg debugging: Set the DEBUG environment variable.

   DEBUG=bimg ./app

2. Enable libvips traces: Set the VIPS_TRACE environment variable (this will output significant data to stdout).

   VIPS_TRACE=1 ./app

3. Force fatal errors: Set the G_DEBUG environment variable to catch fatal warnings or critical errors.

   export G_DEBUG=fatal-warnings,fatal-criticals

Convert an image to a different format (e.g., PNG, JPEG, WEBP) using bimg.NewImage(buffer).Convert(format).

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Convert(bimg.PNG)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

if bimg.NewImage(newImage).Type() == "png" {
  fmt.Fprintln(os.Stderr, "The image was converted into png")
}

You can resize an image using bimg.NewImage(buffer).Resize(width, height). This method preserves the aspect ratio by default. To resize without preserving the aspect ratio, use ForceResize(width, height).

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Resize(800, 600)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

size, err := bimg.NewImage(newImage).Size()
if size.Width == 800 && size.Height == 600 {
  fmt.Println("The image size is valid")
}

bimg.Write("new.jpg", newImage)

Use the Watermark(watermark) method with a bimg.Watermark struct to add text or image watermarks.

bimg.Watermark fields:

• Text (string)
• Opacity (float64)
• Width (int)
• DPI (int)
• Margin (int)
• Font (string)
• Background (bimg.Color)

bimg.Color is defined as {R, G, B}.

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

watermark := bimg.Watermark{
  Text:       "Chuck Norris (c) 2315",
  Opacity:    0.25,
  Width:      200,
  DPI:        100,
  Margin:     150,
  Font:       "sans bold 12",
  Background: bimg.Color{255, 255, 255},
}

newImage, err := bimg.NewImage(buffer).Watermark(watermark)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)

Rotate an image by a specific degree using bimg.NewImage(buffer).Rotate(angle).

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Rotate(90)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)

Use the Process(options) method with a bimg.Options struct to perform multiple operations (resize, crop, quality, rotation, etc.) in a single call.

Available fields in bimg.Options include:

• Width (int)
• Height (int)
• Crop (bool)
• Quality (int)
• Rotate (int)
• Interlace (bool)

options := bimg.Options{
  Width:        800,
  Height:       600,
  Crop:         true,
  Quality:      95,
  Rotate:       180,
  Interlace:    true,
}

buffer, err := bimg.Read("image.jpg")
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

newImage, err := bimg.NewImage(buffer).Process(options)
if err != nil {
  fmt.Fprintln(os.Stderr, err)
}

bimg.Write("new.jpg", newImage)