Gdk::Pixbuf - red pixel?

Hi,

is it possible to use a Gdk::Pixbuf which consists of i.e 10x10 pixels
of a red colour?
Inside DrawingArea this is easy, but I would like to use simple Pixbufs
which have different colours

Marc H. wrote:

Hi,

is it possible to use a Gdk::Pixbuf which consists of i.e 10x10 pixels
of a red colour?
Inside DrawingArea this is easy, but I would like to use simple Pixbufs
which have different colours

Try:
pb = Gdk::Pixbuf.new(Gdk::Pixbuf::COLORSPACE_RGB, false, 8, 10, 10)
pb.fill!(0xff0000ff)

Just in case it interests anyone, here’s an example that uses basic
Gdk::Pixbuf functions to draw a red rectangle around a specified region
of the image & reduce the saturation of the surrounding image:

—8<—
require ‘gdk_pixbuf2’

Rect = Struct.new(“Rect”, :x, :y, :w, :h)

file = ARGV[0] ||
‘/home/geoff/Desktop/iStock/iStock_000001958797XSmall.jpg’

pb = Gdk::Pixbuf.new(file)

Sample crop area

crop = Rect.new(pb.width / 4, pb.height / 4, pb.width / 2, pb.height /
2)

Make pixbuf red (for border)

red_pb = pb.dup
red_pb.fill!(0xff0000ff)

Make greyed out/pixelated pixbuf for background

grey_pb = pb.saturate_and_pixelate(0.2, true)

Box for border

box = Rect.new(crop.x - 2, crop.y - 2, crop.w + 4, crop.h + 4)

Ensure that border doesn’t overflow image

box.x = [box.x,0].max
box.y = [box.y,0].max
box.w = [box.w, red_pb.width - box.x].min
box.h = [box.h, red_pb.height - box.y].min

Use red pixbuf as border background

red_pb.copy_area(box.x, box.y, box.w, box.h, grey_pb, box.x, box.y)

Copy pristine image into the crop area

pb.copy_area(crop.x, crop.y, crop.w, crop.h, grey_pb, crop.x, crop.y)

pb = grey_pb

pb.save(file + ‘.out.jpeg’, ‘jpeg’, :quality => 80)

—8<—


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Whoa, cool stuff … in fact looks like a “filter” for a
dungeon-like map on some images, reminds me of old indiana
jones game in a dark maze :slight_smile:

And thanks by the way!

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