Object
Image is the abstract base class for Image::IndexedColor and Image::TrueColor.
Image objects are created either as a blank array of pixels:
image = Image::IndexedColor.new(width, height) image = Image::TrueColor.new(width, height)
or by loading image data from a file or a string containing one of the supported image formats:
image = Image.load(file) image = Image.load(string)
or by importing image data from a file given by its pathname:
image = Image.import(filename)
After manipulating an image, it can be exported to a string in one of the supported image formats:
image.jpeg(quality = nil) image.png(level = nil) image.gif image.wbmp(fgcolor) image.gd image.gd2(fmt = FMT_COMPRESSED)
or to a file in a format determined by the filename extension:
image.export(filename, options = {})
Import an image from a file with the given filename. The :format option or the file extension is used to determine the image type (jpeg, png, gif, wbmp, gd, gd2, xbm, or xpm). The resulting image will be either of class Image::TrueColor or Image::IndexedColor.
If the file format is gd2, it is optionally possible to extract only a part of the image. Use options :x, :y, :width, and :height to specify the part of the image to import.
# File lib/gd2/image.rb, line 155 def self.import(filename, options = {}) unless format = options.delete(:format) md = filename.match /\.([^.]+)\z/ format = md ? md[1].downcase : nil end format = format.to_sym if format if format == :xpm raise ArgumentError, "Unexpected options #{options.inspect}" unless options.empty? ptr = SYM[:gdImageCreateFromXpm].call(filename)[0] elsif format == :gd2 && !options.empty? x, y, width, height = options.delete(:x) || 0, options.delete(:y) || 0, options.delete(:width) || options.delete(:w), options.delete(:height) || options.delete(:h) raise ArgumentError, "Unexpected options #{options.inspect}" unless options.empty? raise ArgumentError, 'Missing required option :width' if width.nil? raise ArgumentError, 'Missing required option :height' if height.nil? ptr = File.open(filename, 'rb') do |file| SYM[:gdImageCreateFromGd2Part].call(file, x, y, width, height)[0] end else raise ArgumentError, "Unexpected options #{options.inspect}" unless options.empty? create_sym = { :jpeg => :gdImageCreateFromJpeg, :jpg => :gdImageCreateFromJpeg, :png => :gdImageCreateFromPng, :gif => :gdImageCreateFromGif, :wbmp => :gdImageCreateFromWBMP, :gd => :gdImageCreateFromGd, :gd2 => :gdImageCreateFromGd2, :xbm => :gdImageCreateFromXbm }[format] raise UnrecognizedImageTypeError, 'Format (or file extension) is not recognized' unless create_sym ptr = File.open(filename, 'rb') { |file| SYM[create_sym].call(file)[0] } end raise LibraryError unless ptr init_image_ptr(ptr) image = (image_true_color?(ptr) ? TrueColor : IndexedColor).allocate.init_with_image(ptr) block_given? ? yield(image) : image end
Load an image from a file or a string. The image type is detected automatically (JPEG, PNG, GIF, WBMP, or GD2). The resulting image will be either of class Image::TrueColor or Image::IndexedColor.
# File lib/gd2/image.rb, line 90 def self.load(src) case src when File pos = src.pos magic = src.read(4) src.pos = pos create = { :jpeg => :gdImageCreateFromJpeg, :png => :gdImageCreateFromPng, :gif => :gdImageCreateFromGif, :wbmp => :gdImageCreateFromWBMP, :gd2 => :gdImageCreateFromGd2 } args = [src.to_ptr] when String magic = src create = { :jpeg => :gdImageCreateFromJpegPtr, :png => :gdImageCreateFromPngPtr, :gif => :gdImageCreateFromGifPtr, :wbmp => :gdImageCreateFromWBMPPtr, :gd2 => :gdImageCreateFromGd2Ptr } args = [src.length, src] else raise TypeError, 'Unexpected argument type' end type = data_type(magic) or raise UnrecognizedImageTypeError, 'Image data format is not recognized' ptr = SYM[create[type]].call(*args)[0] raise LibraryError unless ptr init_image_ptr(ptr) image = (image_true_color?(ptr) ? TrueColor : IndexedColor).allocate.init_with_image(ptr) block_given? ? yield(image) : image end
Create a new image of the specified dimensions. The default image class is Image::TrueColor; call this method on Image::IndexedColor instead if a palette image is desired.
# File lib/gd2/image.rb, line 76 def self.new(w, h) image = (self == Image) ? TrueColor.new(w, h) : allocate.init_with_size(w, h) block_given? ? yield(image) : image end
Compare this image with another image. Returns false if the images are not identical.
# File lib/gd2/image.rb, line 270 def ==(other) (compare(other) & CMP_IMAGE).zero? end
Return the color of the pixel at image location (x, y).
# File lib/gd2/image.rb, line 316 def [](x, y) pixel2color(get_pixel(x, y)) end
Set the color of the pixel at image location (x, y).
# File lib/gd2/image.rb, line 321 def []=(x, y, color) set_pixel(x, y, color2pixel(color)) end
Set whether colors should be alpha blended with existing colors when pixels are modified. Alpha blending is not available for IndexedColor images.
# File lib/gd2/image.rb, line 372 def alpha_blending=(bool) SYM[:gdImageAlphaBlending].call(image_ptr, bool ? 1 : 0) end
Return true if colors will be alpha blended into the image when pixels are modified. Returns false if colors will be copied verbatim into the image without alpha blending when pixels are modified.
# File lib/gd2/image.rb, line 365 def alpha_blending? not image_ptr[:alphaBlendingFlag].zero? end
Return the aspect ratio of this image, as a floating point ratio of the width to the height.
# File lib/gd2/image.rb, line 299 def aspect width.to_f / height end
Return the current clipping rectangle. Use Image#with_clipping to temporarily modify the clipping rectangle.
# File lib/gd2/image.rb, line 403 def clipping r, rs = SYM[:gdImageGetClip].call(image_ptr, 0, 0, 0, 0) rs[1, 4] end
Return true if the current clipping rectangle excludes the given point.
# File lib/gd2/image.rb, line 424 def clips?(x, y) SYM[:gdImageBoundsSafe].call(image_ptr, x, y)[0].zero? end
Return a pixel value for the given color object.
# File lib/gd2/image.rb, line 346 def color2pixel(color) color.rgba end
Compare this image with another image. Returns 0 if the images are identical, otherwise a bit field indicating the differences. See the GD2::CMP_* constants for individual bit flags.
# File lib/gd2/image.rb, line 264 def compare(other) SYM[:gdImageCompare].call(image_ptr, other.image_ptr)[0] end
Copy a portion of another image to this image. If src_w and src_h are specified, the indicated portion of the source image will be resized (and resampled) to fit the indicated dimensions of the destination.
# File lib/gd2/image.rb, line 548 def copy_from(other, dst_x, dst_y, src_x, src_y, dst_w, dst_h, src_w = nil, src_h = nil) raise ArgumentError unless src_w.nil? == src_h.nil? if src_w SYM[:gdImageCopyResampled].call(image_ptr, other.image_ptr, dst_x, dst_y, src_x, src_y, dst_w, dst_h, src_w, src_h) else SYM[:gdImageCopy].call(image_ptr, other.image_ptr, dst_x, dst_y, src_x, src_y, dst_w, dst_h) end self end
Copy a portion of another image to this image, rotating the source portion first by the indicated angle (in radians). The dst_x and dst_y arguments indicate the center of the desired destination, and may be floating point.
# File lib/gd2/image.rb, line 565 def copy_from_rotated(other, dst_x, dst_y, src_x, src_y, w, h, angle) SYM[:gdImageCopyRotated].call(image_ptr, other.image_ptr, dst_x.to_f, dst_y.to_f, src_x, src_y, w, h, angle.to_degrees.round) self end
Like Image#crop! except a new image is returned.
# File lib/gd2/image.rb, line 604 def crop(x, y, w, h) clone.crop!(x, y, w, h) end
Crop this image to the specified dimensions, such that (x, y) becomes (0, 0).
# File lib/gd2/image.rb, line 597 def crop!(x, y, w, h) ptr = self.class.create_image_ptr(w, h, alpha_blending?) SYM[:gdImageCopy].call(ptr, image_ptr, 0, 0, x, y, w, h) init_with_image(ptr) end
Provide a drawing environment for a block. See GD2::Canvas.
# File lib/gd2/image.rb, line 429 def draw #:yields: canvas yield Canvas.new(self) self end
Duplicate this image, copying all pixels to a new image. Contrast with Image#clone which produces a shallow copy and shares internal pixel data.
# File lib/gd2/image.rb, line 257 def dup self.class.superclass.load(gd2(FMT_RAW)) end
Iterate over each row of pixels in the image, returning an array of pixel values.
# File lib/gd2/image.rb, line 327 def each # optimize for speed get_pixel = SYM[:gdImageGetPixel] ptr = image_ptr (0...height).each do |y| row = (0...width).inject(Array.new(width)) do |row, x| row[x] = get_pixel.call(ptr, x, y).at(0) row end yield row end end
Export this image to a file with the given filename. The image format is determined by the :format option, or by the file extension (jpeg, png, gif, wbmp, gd, or gd2). Returns the size of the written image data. Additional options are as arguments for the Image#jpeg, Image#png, Image#wbmp, or Image#gd2 methods.
# File lib/gd2/image.rb, line 446 def export(filename, options = {}) unless format = options.delete(:format) md = filename.match /\.([^.]+)\z/ format = md ? md[1].downcase : nil end format = format.to_sym if format case format when :jpeg, :jpg write_sym = :gdImageJpeg args = [nil, options.delete(:quality) || -1] when :png write_sym = :gdImagePngEx args = [nil, options.delete(:level) || -1] when :gif write_sym = :gdImageGif args = [nil] when :wbmp write_sym = :gdImageWBMP fgcolor = options.delete(:fgcolor) raise ArgumentError, 'Missing required option :fgcolor' if fgcolor.nil? args = [color2pixel(fgcolor), nil] when :gd write_sym = :gdImageGd args = [nil] when :gd2 write_sym = :gdImageGd2 args = [nil, options.delete(:chunk_size) || 0, options.delete(:fmt) || FMT_COMPRESSED] else raise UnrecognizedImageTypeError, 'Format (or file extension) is not recognized' end raise ArgumentError, "Unrecognized options #{options.inspect}" unless options.empty? File.open(filename, 'wb') do |file| args[args[0].nil? ? 0 : 1] = file SYM[write_sym].call(image_ptr, *args) file.pos end end
Encode and return data for this image in “.gd” format. This is an internal format used by the gd library to quickly read and write images.
# File lib/gd2/image.rb, line 530 def gd ptr, rs = SYM[:gdImageGdPtr].call(image_ptr, 0) ptr.free = SYM[:gdFree] ptr[0, rs[1]] end
Encode and return data for this image in “.gd2” format. This is an internal format used by the gd library to quickly read and write images. The specified fmt may be either GD2::FMT_RAW or GD2::FMT_COMPRESSED.
# File lib/gd2/image.rb, line 539 def gd2(fmt = FMT_COMPRESSED, chunk_size = 0) ptr, rs = SYM[:gdImageGd2Ptr].call(image_ptr, chunk_size, fmt, 0) ptr.free = SYM[:gdFree] ptr[0, rs[3]] end
Return the pixel value at image location (x, y).
# File lib/gd2/image.rb, line 304 def get_pixel(x, y) SYM[:gdImageGetPixel].call(@image_ptr, x, y).at(0) end
Encode and return data for this image in GIF format. Note that GIF only supports palette images; TrueColor images will be automatically converted to IndexedColor internally in order to create the GIF. Use Image#to_indexed_color to control this conversion more precisely.
# File lib/gd2/image.rb, line 512 def gif ptr, rs = SYM[:gdImageGifPtr].call(image_ptr, 0) ptr.free = SYM[:gdFree] ptr[0, rs[1]] end
Return the height of this image, in pixels.
# File lib/gd2/image.rb, line 287 def height image_ptr[:sy] end
Set whether this image will be stored in interlaced form when output as PNG or JPEG.
# File lib/gd2/image.rb, line 358 def interlaced=(bool) SYM[:gdImageInterlace].call(image_ptr, bool ? 1 : 0) end
Return true if this image will be stored in interlaced form when output as PNG or JPEG.
# File lib/gd2/image.rb, line 352 def interlaced? not image_ptr[:interlace].zero? end
Encode and return data for this image in JPEG format. The quality argument should be in the range 0–95, with higher quality values usually implying both higher quality and larger sizes.
# File lib/gd2/image.rb, line 493 def jpeg(quality = nil) ptr, rs = SYM[:gdImageJpegPtr].call(image_ptr, 0, quality || -1) ptr.free = SYM[:gdFree] ptr[0, rs[1]] end
Merge a portion of another image into this one by the amount specified as pct (a percentage). A percentage of 1.0 is identical to Image#copy_from; a percentage of 0.0 is a no-op. Note that alpha channel information from the source image is ignored.
# File lib/gd2/image.rb, line 575 def merge_from(other, dst_x, dst_y, src_x, src_y, w, h, pct) SYM[:gdImageCopyMerge].call(image_ptr, other.image_ptr, dst_x, dst_y, src_x, src_y, w, h, pct.to_percent.round) self end
Consolidate duplicate colors in this image, and eliminate all unused palette entries. This only has an effect on IndexedColor images, and is rather expensive. Returns the number of palette entries deallocated.
# File lib/gd2/image.rb, line 437 def optimize_palette # implemented by subclass end
Return a Color object for the given pixel value.
# File lib/gd2/image.rb, line 341 def pixel2color(pixel) Color.new_from_rgba(pixel) end
Encode and return data for this image in PNG format. The level argument should be in the range 0–9 indicating the level of lossless compression (0 = none, 1 = minimal but fast, 9 = best but slow).
# File lib/gd2/image.rb, line 502 def png(level = nil) ptr, rs = SYM[:gdImagePngPtrEx].call(image_ptr, 0, level || -1) ptr.free = SYM[:gdFree] ptr[0, rs[1]] end
Like Image#polar_transform! except a new image is returned.
# File lib/gd2/image.rb, line 652 def polar_transform(radius) clone.polar_transform!(radius) end
Transform this image into a new image of width and height radius × 2, in which the X axis of the original has been remapped to θ (angle) and the Y axis of the original has been remapped to ρ (distance from center). Note that the original image must be square.
# File lib/gd2/image.rb, line 644 def polar_transform!(radius) raise 'Image must be square' unless width == height ptr = SYM[:gdImageSquareToCircle].call(image_ptr, radius)[0] raise LibraryError unless ptr init_with_image(ptr) end
Like Image#resize! except a new image is returned.
# File lib/gd2/image.rb, line 636 def resize(w, h, resample = true) clone.resize!(w, h, resample) end
Resize this image to the given dimensions. If resample is true, the image pixels will be resampled; otherwise they will be stretched or shrunk as necessary without resampling.
# File lib/gd2/image.rb, line 625 def resize!(w, h, resample = true) ptr = self.class.create_image_ptr(w, h, false) SYM[resample ? :gdImageCopyResampled : :gdImageCopyResized].call( ptr, image_ptr, 0, 0, 0, 0, w, h, width, height) alpha_blending = alpha_blending? init_with_image(ptr) self.alpha_blending = alpha_blending self end
Like Image#rotate! except a new image is returned.
# File lib/gd2/image.rb, line 591 def rotate(angle, axis_x = width / 2.0, axis_y = height / 2.0) clone.rotate!(angle, axis_x, axis_y) end
Rotate this image by the given angle (in radians) about the given axis coordinates. Note that some of the edges of the image may be lost.
# File lib/gd2/image.rb, line 583 def rotate!(angle, axis_x = width / 2.0, axis_y = height / 2.0) ptr = self.class.create_image_ptr(width, height, alpha_blending?) SYM[:gdImageCopyRotated].call(ptr, image_ptr, axis_x.to_f, axis_y.to_f, 0, 0, width, height, angle.to_degrees.round) init_with_image(ptr) end
Set whether this image will be stored with full alpha channel information when output as PNG.
# File lib/gd2/image.rb, line 384 def save_alpha=(bool) SYM[:gdImageSaveAlpha].call(image_ptr, bool ? 1 : 0) end
Return true if this image will be stored with full alpha channel information when output as PNG.
# File lib/gd2/image.rb, line 378 def save_alpha? not image_ptr[:saveAlphaFlag].zero? end
Set the pixel value at image location (x, y).
# File lib/gd2/image.rb, line 310 def set_pixel(x, y, value) SYM[:gdImageSetPixel].call(@image_ptr, x, y, value) nil end
Return the size of this image as an array [width, height], in pixels.
# File lib/gd2/image.rb, line 293 def size [width, height] end
Return this image as an IndexedColor image, creating a copy if necessary. colors indicates the maximum number of palette colors to use, and dither controls whether dithering is used.
# File lib/gd2/image.rb, line 671 def to_indexed_color(colors = MAX_COLORS, dither = true) obj = IndexedColor.allocate ptr = SYM[:gdImageCreatePaletteFromTrueColor].call( to_true_color.image_ptr, dither ? 1 : 0, colors)[0] raise LibraryError unless ptr obj.init_with_image(ptr) # fix for gd bug where image->open[] is not properly initialized (0...ptr[:colorsTotal]).each do |i| ptr[:"open[#{i}]"] = 0 end obj end
Return this image as a TrueColor image, creating a copy if necessary.
# File lib/gd2/image.rb, line 664 def to_true_color self end
Return the transparent color for this image, or nil if none has been set.
# File lib/gd2/image.rb, line 390 def transparent pixel = image_ptr[:transparent] pixel == -1 ? nil : pixel2color(pixel) end
Set or unset the transparent color for this image.
# File lib/gd2/image.rb, line 396 def transparent=(color) SYM[:gdImageColorTransparent].call(image_ptr, color.nil? ? -1 : color2pixel(color)) end
Return true if this image is a TrueColor image.
# File lib/gd2/image.rb, line 275 def true_color? kind_of?(TrueColor) # self.class.image_true_color?(image_ptr) end
Like Image#uncrop! except a new image is returned.
# File lib/gd2/image.rb, line 618 def uncrop(x1, y1 = x1, x2 = x1, y2 = y1) clone.uncrop!(x1, y1, x2, y2) end
Expand the left, top, right, and bottom borders of this image by the given number of pixels.
# File lib/gd2/image.rb, line 610 def uncrop!(x1, y1 = x1, x2 = x1, y2 = y1) ptr = self.class.create_image_ptr(x1 + width + x2, y1 + height + y2, alpha_blending?) SYM[:gdImageCopy].call(ptr, image_ptr, x1, y1, 0, 0, width, height) init_with_image(ptr) end
Encode and return data for this image in WBMP format. WBMP currently supports only black and white images; the specified fgcolor will be used as the foreground color (black), and all other colors will be considered “background” (white).
# File lib/gd2/image.rb, line 522 def wbmp(fgcolor) ptr, rs = SYM[:gdImageWBMPPtr].call(image_ptr, 0, color2pixel(fgcolor)) ptr.free = SYM[:gdFree] ptr[0, rs[1]] end
Return the width of this image, in pixels.
# File lib/gd2/image.rb, line 281 def width image_ptr[:sx] end
Temporarily set the clipping rectangle during the execution of a block. Pixels outside this rectangle will not be modified by drawing or copying operations.
# File lib/gd2/image.rb, line 411 def with_clipping(x1, y1, x2, y2) #:yields: image clip = clipping set_clip = SYM[:gdImageSetClip] begin set_clip.call(image_ptr, x1, y1, x2, y2) yield self self ensure set_clip.call(image_ptr, *clip) end end
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