RMagick圆角

Question

需要一个简单的四舍五入的图像方式。我需要角落是透明的。此链接显示了如何通过命令行执行此操作：

http://www.imagemagick.org/Usage/thumbnails/#rounded

我需要的是相应的RMagick\Ruby代码...谢谢!

Answer 1

如果您正在使用回形针，请检查http://loo.no/articles/rounded-corners-with-paperclip

Answer 2

在源代码中包含Rmagick。请确保将include放在类声明中。

require 'rmagick'
include Magick

创建一个方法，如下所示

def thumb(source_image, geometry_string, radius = 10)
  source_image.change_geometry(geometry_string) do |cols, rows, img| 

    # Make a resized copy of the image
    thumb = img.resize(cols, rows)

    # Set a transparent background: pixels that are transparent will be
    # discarded from the source image.
    mask = Image.new(cols, rows) {self.background_color = 'transparent'}

    # Create a white rectangle with rounded corners. This will become the
    # mask for the area you want to retain in the original image.
    Draw.new.stroke('none').stroke_width(0).fill('white').
        roundrectangle(0, 0, cols, rows, radius, radius).
        draw(mask)

    # Apply the mask and write it out
    thumb.composite!(mask, 0, 0, Magick::CopyOpacityCompositeOp)
    thumb
  end
end

像这样调用该方法

source_image = Image.read('my-big-image.jpg').first
thumbnail_image = thumb(source_image, '64x64>', 8)
thumbnail_image.write('thumb.png')

我以这种方式构造它，因为在创建缩略图的时候，我已经打开了用于其他目的的图像。将文件操作放在方法中可能更有意义。

此外，您可能希望了解几何字符串如何在http://www.imagemagick.org/RMagick/doc/imusage.html#geometry中工作

Answer 3

在CarrierWave::RMagick中使用Fitter Man的代码

方法：

def resize_and_round(geometry_string, radius = 10)
  manipulate! do |original|
    original.change_geometry(geometry_string) do |cols, rows, img| 

      # Make a resized copy of the image
      thumb = img.resize(cols, rows)

      # Set a transparent background: pixels that are transparent will be
      # discarded from the source image.
      mask = Magick::Image.new(cols, rows) {self.background_color = 'transparent'}

      # Create a white rectangle with rounded corners. This will become the
      # mask for the area you want to retain in the original image.
      Magick::Draw.new.stroke('none').stroke_width(0).fill('white').
          roundrectangle(0, 0, cols, rows, radius, radius).
          draw(mask)

      # Apply the mask and write it out
      thumb.composite!(mask, 4,4, Magick::CopyOpacityCompositeOp)
      thumb
    end
  end
end

使用：

process :resize_and_round => ['200x200', 20]