Forum: Ruby-Gnome 2 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 Heiler 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   :)

And thanks by the way!