node-gd extended with features making image processing easier: open an image of any supported format; resize an image doing no math at all; put watermarks like a boss.
// Require library
gd = require('easy-gd')
// Open an image
gd.createFrom('photo.jpeg', function (err, image) {
// Resize image to fit into 800x600
var resized = image.resized({width: 800, height: 600})
// Open watermark image
gd.createFrom('watermark.png', function (err, watermark) {
// Put the watermark at the bottom right corner
resized.watermark(watermark, {x:1, y:1})
// Save result with target format inherited from the source image
// {ext} gets automatically replaced with 'jpg'
resized.save('resized.{ext}', {jpegquality: 90}, function (err, watermark) {
console.log('Done')
})
})
})Arguments
- filename – A name of the file to open.
- callback(err, image) – A callback which is called when the image is loaded or error occured. Image is a conventional gd.Image object extended with format property, being 'jpg', 'gif' or 'png'.
Example
gd.createFrom('./picture.jpeg', function (err, image) {
if (err) {
console.log('Error loading image: ' + err)
} else {
console.log('%s %dx%d loaded', image.format, image.width, image.height)
}
})Arguments
- buffer – A Buffer object to read the image from.
- callback(err, image) – A callback which is called when the image is loaded or error occured. Image is a conventional gd.Image object extended with format property, being 'jpg', 'gif' or 'png'.
Example
// A file came from somewhere
gd.createFromPtr(file.data, function (err, image) {
if (err) {
console.log('Error loading image: ' + err)
} else {
console.log('%s %dx%d loaded', image.format, image.width, image.height)
}
})Arguments
- buffer – A Buffer object with an image to get the format of.
Example
// A file came from somewhere
try {
var format = gd.getFormatPtr(buffer)
console.log('Got ' + format)
} catch (err) {
console.log('Error parsing image format: ' + err)
}Arguments
- filename – A file to save the image to. '{ext}' substring in the filename will be replaced with an actual file extention based on the chosen format.
- options – An object representing save() settings:
- format (optional) – A string with target file format, 'jpeg', 'png' or 'gif' in any letter case.
- jpegquality (optional, JPEG format only) – A number from 0 to 100, controlling generated JPEG quality.
- pnglevel (optional, PNG fornat only) – A number from 0 to 9, controlling generated PNG compression level.
- defaultFormat (optional) – same as format, but is used only if no format option provided and the image.format is undefined.
- callback(err) – A callback which is called when the image is written or some error occured.
Example
// Convert the image to lossy, but lighter format
gd.createFrom('theimage.png', function (err, image) {
image.save('theimage.{ext}', {format: 'jpeg', jpegquality: 80}, function (err) {
console.log(err || 'Success!')
})
})Arguments
- options – An object representing save() settings:
- format (optional) – A string with target file format, 'jpeg', 'png' or 'gif' in any letter case.
- jpegquality (optional, JPEG format only) – A number from 0 to 100, controlling generated JPEG quality.
- pnglevel (optional, PNG fornat only) – A number from 0 to 9, controlling generated PNG compression level.
- defaultFormat (optional) – same as format, but is used only if no format option provided and the image.format is undefined.
Example
gd.createFrom('theimage.png', function (err, image) {
try {
var buffer = image.ptr({format: 'jpeg', jpegquality: 80})
} catch (err) {
return console.log('Error: ' + err)
}
// Output the image from buffer
})Arguments
- options – An objects representing rezied() settings:
- width (optional) – An integer representing desired image width.
- height (optional) – An integer representing desired image height.
- method (optional) – resizing method, recognized values are 'crop' and any other for 'scale', including undefined.
resized() can handle only height or only width options alone, producing result as follows:
- width and height – Scale the image proportionally to fit into width x height pixels.
- width only – Scale the image proportionally to given width, height being computed automatically.
- height only – Scale the image proportionally to given height, width being computed automatically.
- width and height, method='crop' – Scale the image proportionally and crop to make it width x height pixels exactly.
- width only, method='crop' – Crop the image width to given, leaving initial height.
- height only, method='crop' – Crop the image height to given, leaving initial width.
Example
// Open a 100x50 pixels image
gd.createFrom('100x50.png', function (err, image) {
try{
// Scale to fit 50x50, gets image of 50x25
var resized = image.resized({width: 50, height: 50})
// Scale to fit 50 by width, gets image of 50x25
var resized = image.resized({width: 50})
// Scale to fit 30 by height, gets image of 60x30
var resized = image.resized({height: 30})
// Crop to 50x50
var resized = image.resized({width: 50, height: 50, method: 'crop'})
} catch (err) {
console.log('Error: ' + err)
}
})Arguments
- options – An objects representing resizedPtr() settings:
- width (optional) – An integer representing desired image width.
- height (optional) – An integer representing desired image height.
- method (optional) – resizing method, recognized values are 'crop' and any other for 'scale', including undefined.
- format (optional) – A string with target file format, 'jpeg', 'png' or 'gif' in any letter case.
- jpegquality (optional, JPEG format only) – A number from 0 to 100, controlling generated JPEG quality.
- pnglevel (optional, PNG fornat only) – A number from 0 to 9, controlling generated PNG compression level.
- defaultFormat (optional) – same as format, but is used only if no format option provided and the image.format is undefined.
resizedPtr() can handle only height or only width options alone, producing result as follows:
- width and height – Scale the image proportionally to fit into width x height pixels.
- width only – Scale the image proportionally to given width, height being computed automatically.
- height only – Scale the image proportionally to given height, width being computed automatically.
- width and height, method='crop' – Scale the image proportionally and crop to make it width x height pixels exactly.
- width only, method='crop' – Crop the image width to given, leaving initial height.
- height only, method='crop' – Crop the image height to given, leaving initial width.
Example
gd.createFrom('theimage.png', function (err, image) {
try {
var buffer = image.resizedPtr({format: 'jpeg', jpegquality: 80, width: 800, height:600})
} catch (err) {
return console.log('Error: ' + err)
}
// Output the image from buffer
})Arguments
- watermark – A gd.Image representing a watermark.
- position – An object representing watermark positon or an array of such objects. Position is defined by two properties, x and y, being floating point numbers from 0 to 1. {x: 0, y:0 } is the left top corner of the image, {x: 1, y: 1} is the right bottom. If an array of positions given, watermark() examines brightness of the watermark and the image and selects position with the biggest brightness difference.
Example
// Open or create an image and the watermark
// Put the watermark at the bottom right corner
image.watermark(watermark, {x:1, y:1})
// Put the watermark at the center
image.watermark(watermark, {x:0.5, y:0.5})
// Put the watermark at one of the corners of the image where the watermark will be the most contrast
image.watermark(watermark, [{x:0, y:0}, {x:0, y:1}, {x:1, y:1}, {x:1, y:0}])Copyright (C) 2013 Alexander Schepanovski, Egor Balyshev
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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