A Swift-y convenience for loading/saving and manipulating bitmap images.
I wanted a simple Swift interface for wrapping some of the common image manipulations that I come across in my day-to-day image needs, the primary being easily being able to draw directly into a bitmap image.
- Supports all Apple platforms (with some limitations on watchOS)
- supports loading non-RGBA format images (eg. CMYK) by converting the image to RGBA during load.
- objects are easily saved via its
representationproperty. - supports both mutable and immutable methods (functional-style) for manipulating bitmaps.
- bitmap manipulation functions
Sendablesupport to push bitmap information between tasks.
The Bitmap object represents an RGBA image. The image data is stored internally in a simple 1-D array of bytes
representing the R,G,B,A sequence of pixels.
The bitmap object holds and manages a CGContext representation of the bitmap to allow CG- operations directly
on the bitmap itself.
Bitmaps coordinate system starts at (0, 0) in the bottom left.- All operations/manipulations/coordinates occur from the bottom left.
Nice and simple :-)
var bitmap = try Bitmap(width: 640, height: 480)Supports any file formats that NSImage, UIImage and CGImageSource support when loading.
// From a file...
var bitmap = try Bitmap(fileURL: ...)
// From image data
var bitmap = try Bitmap(imageData: ...)Supports any file formats that NSImage, UIImage and CGImageSource support when saving.
Bitmap provides methods for writing to some different formats, such as png.
The representation property on the bitmap contains the methods for generating
image data in different formats
var bitmap = try Bitmap(fileURL: ...)
...
let pngData = bitmap.representation?.png()var bitmap = try Bitmap(width: 640, height: 480)
bitmap.draw { ctx in
ctx.setFillColor(.black)
ctx.fill([CGRect(x: 5, y: 5, width: 20, height: 20)])
}var bitmap = try Bitmap(width: 640, height: 480)
// Draw an image into a defined rectangle (with optional scaling types aspectFit, aspectFill, axes independent)
bitmap.drawImage(image, in: CGRect(x: 50, y: 50, width: 100, height: 100))
// Draw a bitmap at a point
bitmap.drawBitmap(bitmap, at: CGPoint(x: 300, y: 300))You can directly access pixel information in the bitmap using subscripts or the get/setPixel methods on Bitmap
var bitmap = Bitmap(...)
// Retrieve the color of the pixel at x = 4, y = 3.
let rgbaPixel = bitmap[4, 3] // or bitmap.getPixel(x: 4, y: 3)
// Set the color of the pixel at x = 4, y = 3. Only available when `bitmap` is mutable
bitmap[4, 3] = Bitmap.RGBA(r: 255, g: 0, b: 0, a: 255) // or bitmap.setPixel(x: 4, y: 3, ...)Bitmap provides a number of built-in operations (such as rotate, tint) that operate on a Bitmap instance.
Mutable functions operate on a Bitmap variable. Each method modifies the original bitmap instance.
// Load an image, rotate it and convert it to grayscale
var bitmap = try Bitmap(fileURL: ...)
try bitmap.rotate(by: 1.4)
try bitmap.grayscale()Immutable functions work on a copy of the bitmap and return the copy. The original bitmap (which can be a let variable
remains untouched.
Immutable function variations are named with 'ing' in the title, such as tinting() or scaling().
// Load an image, rotate it and convert it to grayscale
let bitmap = try Bitmap(fileURL: ...)
let rotated = try bitmap.rotating(by: 1.4)
let grayscale = try rotated.grayscaling()This allows functional-style chaining on a bitmap.
// Functional style
let bitmap = try Bitmap(fileURL: ...)
.rotating(by: 1.4)
.grayscaling()- Resizing/scaling
- Padding/inset
- Clipping/masking
- Rotation
- Scrolling
- Transparency removal
- Punching holes
- Color manipulation (eg. grayscale, tinting, gamma adjustment, saturation etc)
- Flipping
- Drawing (eg. lines, shapes, paths, fill/stroke)
- Drawing text
- Drawing borders
… and more!
You will not be able to directly send a Bitmap object between Tasks.
This is due to Bitmap internally caching a CGContext instance in order to increase performance and
reduce the memory footprint.
Internally, Bitmap keeps pixel information inside a Bitmap.RGBAData object which conforms to Sendable.
This object can be passed safely between tasks and are easily reconstituted into a new Bitmap object.
var myBitmap = try Bitmap(...)
let bitmapData = myBitmap.bitmapData
// Pass `bitmapData` to another Task
var myBitmap = try Bitmap(bitmapData)MIT License
Copyright (c) 2024 Darren Ford
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