Class: Knj::Image
Overview
This class holds methods to manipulate images.
Class Method Summary collapse
-
.height_for_width(orig_width, orig_height, new_width) ⇒ Object
Returns the height relative to the width.
-
.rounded_corners(args) ⇒ Object
This function can make rounded transparent corners on an image with a given radius.
-
.width_for_height(orig_width, orig_height, new_height) ⇒ Object
Returns the width relative to the height.
Class Method Details
.height_for_width(orig_width, orig_height, new_width) ⇒ Object
Returns the height relative to the width.
Examples
Knj::Image.height_for_width(640, 480, 533) #=> 399
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# File 'lib/knj/image.rb', line 175 def self.height_for_width(orig_width, orig_height, new_width) return (orig_height.to_f / (orig_width.to_f / new_width.to_f)).to_i end |
.rounded_corners(args) ⇒ Object
This function can make rounded transparent corners on an image with a given radius. Further more it can also draw borders around the entire image in a given color and take the border into account.
Examples
img = Magick::Image.read(path_str) Knj::Image.rounded_corners(
:img => img,
:radius => 25,
:border => 1,
:border_color => "#000000"
)
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# File 'lib/knj/image.rb', line 12 def self.rounded_corners(args) raise "No or invalid ':img' given: '#{args}'." if !args[:img] raise "No or invalid ':radius' given: '#{args}'." if !args[:radius].respond_to?("to_i") or args[:radius].to_i <= 0 pic = args[:img] r = args[:radius].to_i r_half = r / 2 r2 = r * r d = r * 2 center_x = r - 1 center_y = 1 coords = {} 0.upto(r) do |x| y = center_y + Math.sqrt(r2 - ((x - center_x) * (x - center_x))) coords[x] = y.to_i end if args[:border] draw = Magick::Draw.new draw.stroke(args[:border_color]) draw.stroke_width(1) 0.upto(args[:border] - 1) do |x| draw.line(x, 0, x, pic.rows) draw.line(pic.columns-x-1, 0, pic.columns-x-1, pic.rows) draw.line(0, x, pic.columns, x) draw.line(0, pic.rows-x-1, pic.columns, pic.rows-x-1) end draw.draw(pic) end borders = [] if args[:border] 1.upto(4) do |count| r.times do |x| border_from = nil border_to = nil border_mode = nil case count when 1 x_from = x y_from = 0 y_to = r - coords[x] if borders and x > 0 and x < r_half border_from = y_to border_to = r - coords[x - 1] border_to = 1 if border_to < 1 #top left borders << {:x => x_from, :yf => border_from, :yt => border_to} borders << {:y => x_from, :xf => border_from, :xt => border_to} #top right borders << {:x => pic.columns - x - 1, :yf => border_from, :yt => border_to} borders << {:y => x_from, :xf => pic.columns - border_to, :xt => pic.columns - border_from} #bottom left borders << {:x => x_from, :yf => pic.rows - border_to, :yt => pic.rows - border_from} borders << {:y => pic.rows - x - 1, :xf => border_from, :xt => border_to} #bottom right borders << {:x => pic.columns - x - 1, :yf => pic.rows - border_to, :yt => pic.rows - border_from} borders << {:y => pic.rows - x - 1, :xf => pic.columns - border_to, :xt => pic.columns - border_from} end when 2 x_from = pic.columns - r + x y_from = 0 y_to = r - coords[r - x - 1] when 3 x_from = x y_from = pic.rows - r + coords[x] y_to = pic.rows - y_from when 4 x_from = pic.columns - r + x y_from = pic.rows - r + coords[r - x - 1] y_to = pic.rows - y_from end next if y_to <= 0 #Make corners transparent. if false or RUBY_ENGINE == "jruby" #Make up for the fact that "get_pixels" has not been implemented in "rmagick4j"... pixels = [] 0.upto(y_to) do |count| pixels << Magick::Pixel.new(0, 0, 0, 255) end pic.store_pixels(x_from, y_from, 1, y_to, pixels) else pixels = pic.get_pixels(x_from, y_from, 1, y_to) pixels.each do |pixel| pixel.opacity = Magick::TransparentOpacity end pic.store_pixels(x_from, y_from, 1, y_to, pixels) end end end if borders color = args[:border_color] borders.each do |border| if border.key?(:x) count_from = border[:yf] count_to = border[:yt] elsif border.key?(:y) count_from = border[:xf] count_to = border[:xt] end count_from.upto(count_to - 1) do |coord| if RUBY_ENGINE == "jruby" and color[0, 1] == "#" r = color[1, 2].hex b = color[3, 2].hex g = color[5, 2].hex pixel = Magick::Pixel.new(r, b, g) else pixel = Magick::Pixel.from_color(color) end if border.key?(:x) if RUBY_ENGINE == "jruby" pic.store_pixels(border[:x], coord, 1, 1, [pixel]) else pic.pixel_color(border[:x], coord, pixel) end elsif border.key?(:y) if RUBY_ENGINE == "jruby" pic.store_pixels(coord, border[:y], 1, 1, [pixel]) else pic.pixel_color(coord, border[:y], pixel) end end end end end pic.matte = true end |
.width_for_height(orig_width, orig_height, new_height) ⇒ Object
Returns the width relative to the height.
Examples
Knj::Image.width_for_height(640, 480, 400) #=> 533
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# File 'lib/knj/image.rb', line 168 def self.width_for_height(orig_width, orig_height, new_height) return (orig_width.to_f / (orig_height.to_f / new_height.to_f)).to_i end |