PHP imagewbmp() Function: Usage and Examples

Writes a monochrome GD image in WBMP format to a path or output stream; the image must be suitable for black-and-white encoding.

What It Does and When to Use It

Create a small example image and save it using the exact encoder. GD operates on raster images in PHP; Imagick delegates to ImageMagick; EXIF reads metadata and is not an image decoder.

Requirements, Inputs and Expected Behavior

Image decoding and encoding need the relevant GD, EXIF, or Imagick support; features vary by PHP build and server. A successful call is not a reason to trust an unwritable path or an unusable output file.

Example 1: Basic Operation

Create a small example image and save it using the exact encoder.

<?php
$image = imagecreate(16, 16);
 $white = imagecolorallocate($image, 255, 255, 255);
 $black = imagecolorallocate($image, 0, 0, 0);
 imageline($image, 0, 0, 15, 15, $black);
 $destination = __DIR__ . '/line.wbmp';
 try { if (!imagewbmp($image, $destination)) throw new RuntimeException('Image export failed'); }
 finally { imagedestroy($image); }

Example 2: Behavior and Validation

Show the same encoder handling a different source image; ensure the destination is writable.

<?php
$image = imagecreatetruecolor(100, 40);
 $background = imagecolorallocate($image, 240, 240, 240);
 imagefill($image, 0, 0, $background);
 $destination = __DIR__ . '/label.wbmp';
 if (!imagewbmp($image, $destination)) { throw new RuntimeException('Encoder failed'); }
 imagedestroy($image);

Practical Example: Application Use

Verify encoder availability and the file rather than relying on the function name alone.

<?php
if (!function_exists('imagewbmp')) {
     throw new RuntimeException('Required GD encoder unavailable');
 }
 $image = imagecreatetruecolor(4, 4);
 $destination = sys_get_temp_dir() . '/sample.wbmp';
 try {
     if (!imagewbmp($image, $destination) || !is_file($destination)) throw new RuntimeException('No output generated');
     echo filesize($destination), " bytes
";
 } finally { imagedestroy($image); if (is_file($destination)) unlink($destination); }

Important Behavior and Edge Cases

The second example highlights: Show the same encoder handling a different source image; ensure the destination is writable. The practical example adds: Verify encoder availability and the file rather than relying on the function name alone.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Writes a monochrome GD image in WBMP format to a path or output stream; the image must be suitable for black-and-white encoding.
• Verify encoder availability and the file rather than relying on the function name alone.
• Check image dimensions, true decoder availability, and actual output format rather than trusting a filename suffix.