Simple class that providing scaling (rectangle and thumbnails) for images using RMagick and Ruby.
Code:
class ImageScale def change_geometry(sz,value) w = sz[0] ; h = sz[1] if w > h sz[0] = value sz[1] = ((value * h) / w).floor else sz[1] = value sz[0] = ((value * w) / h).floor end return sz end def make_rect(file_in,file_out, width, quality=85, sharp=false) if FileTest.exists?(file_in) begin img = Magick::Image.read(file_in).first img.crop_resized!(width,width, Magick::CenterGravity) img = img.sharpen(0.5, 0.5) if sharp img.write(file_out) { self.quality = quality } return true if FileTest.exists?(file_out) rescue Magick::ImageMagickError return false end end return false end def make_thumb(file_in,file_out, width_to, quality=85, sharp=false) if FileTest.exists?(file_in) begin img = Magick::Image.read(file_in).first info = [img.columns,img.rows] sz = change_geometry(info, width_to) img = img.resize(sz[0],sz[1]) img = img.sharpen(0.5, 0.5) if sharp img.write(file_out) { self.quality = quality } return true if FileTest.exists?(file_out) rescue Magick::ImageMagickError return false end end return false end end
Ok, let`s see how this class working. For example, we have source image:
Function ImageScale.make_rect(src,dest,64) will produce such image:
Function ImageScale.make_thumb(src,dest,200) will produce thumbnail:
There is optional parameter sharp to use sharping. Optional parameter quality is set to 85% compression value.