module CrImage::Operation::MaskApply

Overview

Apply a mask to an image

Taking sample image:

Woman with black turtleneck and white background

And mask

Black box with thin horizontal white box at eye level 
mask = CrImage::Mask.new(image, false)
mask[50..90, 65..75] = true
mask.to_gray.save("apply_mask_mask.jpg")

image.apply(mask).save("apply_mask.jpg")

image.apply_color(mask, CrImage::Color.of("#00f")).save("apply_mask_color.jpg")

image.apply(mask) do |pixel, channel_type, x, y|
  Math.min(255, pixel + 50).to_u8 if channel_type.blue?
end.save("apply_mask_block.jpg")
Image is blacked out other than thin horizontal bar of the woman's eyes Thin horizontal blue bar over woman's eyes Thin horizantal transparent blue bar over woman's eyes

Direct including types

Defined in:

cr-image/operation/mask_apply.cr

Instance Method Summary

Instance Method Detail

def apply(mask : Mask) : self #

Black out all pixels but those found in the mask


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def apply(mask : Mask, &block : UInt8, ChannelType, Int32, Int32 -> UInt8 | Nil) : self #

Apply block to all pixels that match mask, replacing pixel value if block returns non-nil value.

Does not change values not matched by the mask


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def apply!(mask : Mask) : self #

TODO add apply version that accepts 1+ ChannelType that the mask should apply to (i.e. make a background completely transparent, not just transparent black)


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def apply!(mask : Mask, &block : UInt8, ChannelType, Int32, Int32 -> UInt8 | Nil) : self #

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def apply_color(mask : Mask, color : Color) : self #

Change the color of all pixels that match the mask


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def apply_color!(mask : Mask, color : Color) : self #

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