Module: FreeImage::Transforms

Included in:
Bitmap
Defined in:
lib/free-image/modules/transforms.rb

Instance Method Summary collapse

Instance Method Details

#flip_horizontal! ⇒ Object

call-seq:

bitmap.flip_horizontal -> boolean

Flip the input image horizontally along the vertical axis.



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# File 'lib/free-image/modules/transforms.rb', line 74

def flip_horizontal!
  result = FreeImage.FreeImage_FlipHorizontal(self)
  FreeImage.check_last_error
  result
end

#flip_vertical! ⇒ Object

call-seq:

bitmap.flip_vertical -> boolean

Flip the input image vertically along the horizontal axis.



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# File 'lib/free-image/modules/transforms.rb', line 85

def flip_vertical!
  result = FreeImage.FreeImage_FlipVertical(self)
  FreeImage.check_last_error
  result
end

#rotate(angle, bk_color = nil, &block) ⇒ Object

call-seq:

bitmap.rotate(angle, bk_color) -> bitmap
bitmap.rotate(angle, bk_color) -> {|img| block} -> bitmap

Rotates an image around the center of the image area by means of 3 shears. The rotated image retains the same size and aspect ratio of source image (the resulting image size is usually bigger), so that this function should be used when rotating an image by 90°, 180° or 270°.

When the angle value isn’t an integer multiple of 90°, the background is filled with the supplied bkcolor parameter. When bkcolor is nil, the default value, the background is filled with a black.

Parameters

angle::    Specifies the angle of rotation in degrees
bk_color:: The color used to fill the background.

If an optional block is provided, it will be passed the new image as an argument. The image will be automatically closed when the block completes.



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# File 'lib/free-image/modules/transforms.rb', line 36

def rotate(angle, bk_color = nil, &block)
  ptr = FreeImage.FreeImage_Rotate(self, angle, bk_color)
  FreeImage.check_last_error
  self.class.new(ptr, &block)
end

#rotate_ex(angle, x_shift, y_shift, x_origin, y_origin, use_mask = false, &block) ⇒ Object

call-seq:

bitmap.rotate_ex(aangle, x_shift, y_shift, x_origin, y_origin, use_mask = false) -> bitmap
bitmap.rotate_ex(aangle, x_shift, y_shift, x_origin, y_origin, use_mask = false) {|img| block} -> bitmap

Rotates an image using a 3rd order (cubic) B-Spline. The rotated image will have the same width and height as the source image, so that this function is better suited for computer vision and robotics.

Parameters:

angle::    Specifies the angle of rotation in degrees
x_shift::  Specifies horizonal image translation
y_shift::  Specifies vertical image translation
x_origin:: Specifies the x coordinate of the center of rotation
y_origin:: Specifies the y coordinate of the center of rotation
use_mask:: When true, irrelevant parts of the image are set to black,
           otherwise, a mirroring technique is used to fill irrelevant pixels.

If an optional block is provided, it will be passed the new image as an argument. The image will be automatically closed when the block completes.



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# File 'lib/free-image/modules/transforms.rb', line 63

def rotate_ex(angle, x_shift, y_shift, x_origin, y_origin, use_mask = false, &block)
  ptr = FreeImage.FreeImage_RotateEx(self, angle, x_shift, y_shift, x_origin, y_origin, use_mask)
  FreeImage.check_last_error
  self.class.new(ptr, &block)
end