e5ba6d4afc
Calculate the dimensions of thumbnails ourselves instead of letting libvips calculate them for us. This way we know the exact size of thumbnails, so we can set the right width and height for <img> tags. If we let libvips calculate thumbnail sizes for us, then we can't predict the exact size of thumbnails, because sometimes libvips rounds numbers differently than us.
123 lines
3.4 KiB
Ruby
123 lines
3.4 KiB
Ruby
# A MediaFile for a JPEG, PNG, or GIF file. Uses libvips for resizing images.
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#
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# @see https://github.com/libvips/ruby-vips
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# @see https://libvips.github.io/libvips/API/current
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class MediaFile::Image < MediaFile
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# http://jcupitt.github.io/libvips/API/current/VipsForeignSave.html#vips-jpegsave
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JPEG_OPTIONS = { Q: 90, background: 255, strip: true, interlace: true, optimize_coding: true }
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def dimensions
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image.size
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rescue Vips::Error
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[0, 0]
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end
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def is_corrupt?
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image.stats
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false
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rescue Vips::Error
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true
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end
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def duration
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return nil if !is_animated?
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video.duration
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end
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def frame_count
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if file_ext == :gif
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image.get("n-pages")
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elsif file_ext == :png
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metadata.fetch("PNG:AnimationFrames", 1)
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else
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nil
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end
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end
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def frame_rate
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return nil if !is_animated? || frame_count.nil? || duration.nil? || duration == 0
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frame_count / duration
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end
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def channels
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image.bands
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end
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def colorspace
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image.interpretation
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end
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def resize(max_width, max_height, format: :jpeg, **options)
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# @see https://www.libvips.org/API/current/Using-vipsthumbnail.md.html
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# @see https://www.libvips.org/API/current/libvips-resample.html#vips-thumbnail
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if colorspace == :srgb
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, import_profile: "srgb", export_profile: "srgb", **options)
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elsif colorspace == :cmyk
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# Leave CMYK as CMYK for better color accuracy than sRGB.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, import_profile: "cmyk", export_profile: "cmyk", intent: :relative, **options)
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elsif colorspace == :"b-w" && has_embedded_profile?
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# Convert greyscale to sRGB so that the color profile is properly applied before we strip it.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, export_profile: "srgb", **options)
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elsif colorspace == :"b-w"
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# Otherwise, leave greyscale without a profile as greyscale because
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# converting it to sRGB would change it from 1 channel to 3 channels.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, **options)
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else
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raise NotImplementedError
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end
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output_file = Tempfile.new(["image-preview", ".jpg"])
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resized_image.jpegsave(output_file.path, **JPEG_OPTIONS)
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MediaFile::Image.new(output_file)
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end
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def preview(max_width, max_height, **options)
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w, h = MediaFile.scale_dimensions(width, height, max_width, max_height)
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resize(w, h, size: :force, **options)
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end
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def crop(max_width, max_height)
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resize(max_width, max_height, crop: :attention)
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end
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def preview_frame
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if is_animated?
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FFmpeg.new(file).smart_video_preview
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else
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self
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end
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end
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def is_animated?
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frame_count.to_i > 1
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end
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def is_animated_gif?
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file_ext == :gif && is_animated?
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end
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def is_animated_png?
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file_ext == :png && is_animated?
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end
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# Return true if the image has an embedded ICC color profile.
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def has_embedded_profile?
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image.icc_import(embedded: true)
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true
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rescue Vips::Error
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false
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end
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# @return [Vips::Image] the Vips image object for the file
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def image
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Vips::Image.new_from_file(file.path, fail: true).autorot
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end
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def video
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FFmpeg.new(file)
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end
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memoize :image, :video, :dimensions, :is_corrupt?, :is_animated_gif?, :is_animated_png?
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end
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