cairo: add cairo-only example

.gitignore

@@ -4,3 +4,4 @@
 *.stackdump
 .depcheck
 *.rockspec
+cairodemo-*.png

samples/cairo.lua

@@ -0,0 +1,269 @@
+#! /usr/bin/env lua
+
+--
+-- Sample cairo application, based on http://cairographics.org/samples/
+--
+-- Renders all samples into separate PNG images
+--
+
+local math = require 'math'
+local lgi = require 'lgi'
+local cairo = lgi.cairo
+
+local dir = arg[0]:sub(1, arg[0]:find('[^%/\\]+$') - 1):gsub('[/\\]$', '')
+local imagename = dir .. '/gtk-demo/apple-red.png'
+
+local samples = {}
+
+function samples.arc(cr)
+   local xc, yc = 128, 128
+   local radius = 100
+   local angle1, angle2 = math.rad(45), math.rad(180)
+
+   cr.line_width = 10
+   cr:arc(xc, yc, radius, angle1, angle2)
+   cr:stroke()
+
+   -- draw helping lines
+   cr:set_source_rgba(1, 0.2, 0.2, 0.6)
+   cr.line_width = 6
+
+   cr:arc(xc, yc, 10, 0, math.rad(360))
+   cr:fill()
+
+   cr:arc(xc, yc, radius, angle1, angle1)
+   cr:line_to(xc, yc)
+   cr:arc(xc, yc, radius, angle2, angle2)
+   cr:line_to(xc, yc)
+   cr:stroke()
+end
+
+function samples.arc_negative(cr)
+   local xc, yc = 128, 128
+   local radius = 100
+   local angle1, angle2 = math.rad(45), math.rad(180)
+
+   cr.line_width = 10
+   cr:arc_negative(xc, yc, radius, angle1, angle2)
+   cr:stroke()
+
+   -- draw helping lines
+   cr:set_source_rgba(1, 0.2, 0.2, 0.6)
+   cr.line_width = 6
+
+   cr:arc(xc, yc, 10, 0, math.rad(360))
+   cr:fill()
+
+   cr:arc(xc, yc, radius, angle1, angle1)
+   cr:line_to(xc, yc)
+   cr:arc(xc, yc, radius, angle2, angle2)
+   cr:line_to(xc, yc)
+   cr:stroke()
+end
+
+function samples.clip(cr)
+   cr:arc(128, 128, 76.8, 0, math.rad(360))
+   cr:clip()
+
+   -- current path is not consumed by cairo.Context.clip()
+   cr:new_path()
+
+   cr:rectangle(0, 0, 256, 256)
+   cr:fill()
+   cr:set_source_rgb(0, 1, 0)
+   cr:move_to(0, 0)
+   cr:line_to(256, 256)
+   cr:move_to(256, 0)
+   cr:line_to(0, 256)
+   cr.line_width = 10
+   cr:stroke()
+end
+
+function samples.clip_image(cr)
+   cr:arc(128, 128, 76.8, 0, math.rad(360))
+   cr:clip()
+   cr:new_path()
+
+   local image = cairo.ImageSurface.create_from_png(imagename)
+   cr:scale(256 / image.width, 256 / image.height)
+   cr:set_source_surface(image, 0, 0)
+   cr:paint()
+end
+
+function samples.dash(cr)
+   cr:set_dash({ 50, 10, 10, 10 }, -50)
+
+   cr.line_width = 10
+   cr:move_to(128, 25.6)
+   cr:line_to(230.4, 230.4)
+   cr:rel_line_to(-102.4, 0)
+   cr:curve_to(51.2, 230.4, 51.2, 128, 128, 128)
+
+   cr:stroke()
+end
+
+function samples.curve_to(cr)
+   local x, y = 25.6, 128
+   local x1, y1 = 102.4, 230.4
+   local x2, y2 = 153.6, 25.6
+   local x3, y3 = 230.4, 128
+
+   cr:move_to(x, y)
+   cr:curve_to(x1, y1, x2, y2, x3, y3)
+
+   cr.line_width = 10
+   cr:stroke()
+
+   cr:set_source_rgba(1, 0.2, 0.2, 0.6)
+   cr.line_width = 6
+   cr:move_to(x, y)
+   cr:line_to(x1, y1)
+   cr:move_to(x2, y2)
+   cr:line_to(x3, y3)
+   cr:stroke()
+end
+
+function samples.fill_and_stroke(cr)
+   cr:move_to(128, 25.6)
+   cr:line_to(230.4, 230.4)
+   cr:rel_line_to(-102.4, 0)
+   cr:curve_to(51.2, 230.4, 51.2, 128, 128, 128)
+   cr:close_path()
+
+   cr:move_to(64, 25.6)
+   cr:rel_line_to(51.2, 51.2)
+   cr:rel_line_to(-51.2, 51.2)
+   cr:rel_line_to(-51.2, -51.2)
+   cr:close_path()
+
+   cr.line_width = 10
+   cr:set_source_rgb(0, 0, 1)
+   cr:fill_preserve()
+   cr:set_source_rgb(0, 0, 0)
+   cr:stroke()
+end
+
+function samples.fill_style(cr)
+   cr.line_width = 6
+
+   cr:rectangle(12, 12, 232, 70)
+   cr:new_sub_path()
+   cr:arc(64, 64, 40, 0, math.rad(360))
+   cr:new_sub_path()
+   cr:arc_negative(192, 64, 40, 0, math.rad(-360))
+
+   cr.fill_rule = 'EVEN_ODD'
+   cr:set_source_rgb(0, 0.7, 0)
+   cr:fill_preserve()
+   cr:set_source_rgb(0, 0, 0)
+   cr:stroke()
+
+   cr:translate(0, 128)
+   cr:rectangle(12, 12, 232, 70)
+   cr:new_sub_path()
+   cr:arc(64, 64, 40, 0, math.rad(360))
+   cr:new_sub_path()
+   cr:arc_negative(192, 64, 40, 0, math.rad(-360))
+
+   cr.fill_rule = 'WINDING'
+   cr:set_source_rgb(0, 0, 0.9)
+   cr:fill_preserve()
+   cr:set_source_rgb(0, 0, 0)
+   cr:stroke()
+end
+
+function samples.gradient(cr)
+   local pat = cairo.Pattern.create_linear(0, 0, 0, 256)
+   pat:add_color_stop_rgba(1, 0, 0, 0, 1)
+   pat:add_color_stop_rgba(0, 1, 1, 1, 1)
+   cr:rectangle(0, 0, 256, 256)
+   cr.source = pat
+   cr:fill()
+
+   pat = cairo.Pattern.create_radial(115.2, 102.4, 25.6,
+				     102.4, 102.4, 128)
+   pat:add_color_stop_rgba(0, 1, 1, 1, 1);
+   pat:add_color_stop_rgba(1, 0, 0, 0, 0);
+   cr.source = pat
+   cr:arc(128, 128, 76.8, 0, math.rad(360))
+   cr:fill()
+end
+
+function samples.image(cr)
+   local image = cairo.ImageSurface.create_from_png(imagename)
+
+   cr:translate(128, 128)
+   cr:rotate(math.rad(45))
+   cr:scale(256 / image.width, 256 / image.height)
+   cr:translate(-image.width / 2, -image.height / 2)
+
+   cr:set_source_surface(image, 0, 0)
+   cr:paint()
+end
+
+function samples.imagepattern(cr)
+   local image = cairo.ImageSurface.create_from_png(imagename)
+
+   local pattern = cairo.Pattern.create_for_surface(image)
+   pattern.extend = 'REPEAT'
+
+   cr:translate(128, 128)
+   cr:rotate(math.rad(45))
+   cr:scale(1 / math.sqrt(2), 1 / math.sqrt(2))
+   cr:translate(-128, -128)
+
+   pattern.matrix = cairo.Matrix.create_scale(image.width / 256 * 5,
+					      image.height / 256 * 5)
+   cr.source = pattern
+
+   cr:rectangle(0, 0, 256, 256)
+   cr:fill()
+end
+
+function samples.multisegment_caps(cr)
+   cr:move_to(50, 75)
+   cr:line_to(200, 75)
+
+   cr:move_to(50, 125)
+   cr:line_to(200, 125)
+
+   cr:move_to(50, 175)
+   cr:line_to(200, 175)
+
+   cr.line_width = 30
+   cr.line_cap = 'ROUND'
+   cr:stroke()
+end
+
+function samples.rounded_rectangle(cr)
+   local x, y, width, height = 25.6, 25.6, 204.8, 204.8
+   local aspect = 1
+   local corner_radius = height / 10
+
+   local radius = corner_radius / aspect
+
+   cr:new_sub_path()
+   cr:arc(x + width - radius, y + radius, radius,
+	  math.rad(-90), math.rad(0))
+   cr:arc(x + width - radius, y + height - radius, radius,
+	  math.rad(0), math.rad(90))
+   cr:arc(x + radius, y + height - radius, radius,
+	  math.rad(90), math.rad(180))
+   cr:arc(x + radius, y + radius, radius,
+	  math.rad(180), math.rad(270))
+   cr:close_path()
+
+   cr:set_source_rgb(0.5, 0.5, 1)
+   cr:fill_preserve()
+   cr:set_source_rgba(0.5, 0, 0, 0.5)
+   cr.line_width = 10
+   cr:stroke()
+end
+
+-- Iterate through all samples and create .png files from them
+for name, sample in pairs(samples) do
+   local surface = cairo.ImageSurface.create('ARGB32', 256, 256)
+   local cr = cairo.Context.create(surface)
+   sample(cr)
+   surface:write_to_png('cairodemo-' .. name .. '.png')
+end