;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Andy Wingo <wingo@igalia.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu build svg)
  #:use-module (rsvg)
  #:use-module (cairo)
  #:use-module (srfi srfi-11)
  #:export (svg->png))

(define* (downscaled-surface surface
                             #:key
                             source-width source-height
                             width height)
  "Return a new rendering context where SURFACE is scaled to WIDTH x HEIGHT."
  (let ((cr (cairo-create (cairo-image-surface-create 'argb32
                                                      width height))))
    (cairo-scale cr (/ width source-width) (/ height source-height))
    (cairo-set-source-surface cr surface 0 0)
    (cairo-pattern-set-filter (cairo-get-source cr) 'best)
    (cairo-rectangle cr 0 0 source-width source-height)
    (cairo-fill cr)
    cr))

(define* (svg->png in-svg out-png
                   #:key width height)
  "Render the file at IN-SVG as a PNG file in OUT-PNG.  When WIDTH and HEIGHT
are provided, use them as the dimensions of OUT-PNG; otherwise preserve the
dimensions of IN-SVG."
  (define svg
    (rsvg-handle-new-from-file in-svg))

  (let-values (((origin-width origin-height em ex)
                (rsvg-handle-get-dimensions svg)))
    (let* ((surf (cairo-image-surface-create 'argb32
                                             origin-width origin-height))
           (cr   (cairo-create surf)))
      (rsvg-handle-render-cairo svg cr)
      (cairo-surface-flush surf)
      (let ((cr (if (and width height
                         (not (= width origin-width))
                         (not (= height origin-height)))
                    (downscaled-surface surf
                                        #:source-width origin-width
                                        #:source-height origin-height
                                        #:width width
                                        #:height height)
                    cr)))
        (cairo-surface-write-to-png (cairo-get-target cr) out-png)))))

;;; svg.scm ends here
/guix/commit/gnu/packages/monitoring.scm?id=6b4e4f16bc445dd9187d962d9ca2da97651a1225'>gnu: fswatch: Update to 1.14.0.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-04-15 11:00:15 +0200'>2019-04-15</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=6396829738c884ee4dd75a0c00eee7c3f29218fd'>gnu: fswatch: Don't use NAME in source URI.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-04-08 15:32:02 +0200'>2019-04-08</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=46a7ad4698da5f91d5e968ade7f45599ddd4663c'>gnu: zabbix-agentd: Update to 4.2.0.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2019-02-04 11:46:10 +0100'>2019-02-04</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=05b4b3ea05b2a9e0c769fe3418c54a2819447a25'>gnu: python-prometheus-client: Remove duplicate.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-01-15 14:46:44 +0100'>2019-01-15</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=44d10b1f722856ab8e9b942804aa7ef33e2ef739'>gnu: Separate Python core packages from the rest.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2018-12-17 22:09:11 +0300'>2018-12-17</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=f2f956010c64503daa18cf8138a3264212969c3d'>gnu: zabbix-agentd: Update to 4.0.2.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2018-12-17 22:09:10 +0300'>2018-12-17</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=2c9ac8392ad867f65b1313216dbe7179d6083df5'>gnu: zabbix-server: Split output.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2018-11-05 03:01:21 +0100'>2018-11-05</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=64eb038eef41dc7c1f912dc7097aa53e8b5d8b7c'>gnu: Add fswatch.</a><span class='msg-avail'>...</span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2018-09-02 19:18:16 +0300'>2018-09-02</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=391097782311c82c04b171db7373a0bbfc1d8653'>gnu: monitoring.scm: Fix copyright line.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2018-09-01 19:01:36 +0300'>2018-09-01</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=ead46692ec8a17ed9cf668131343d7cf1b3725e5'>gnu: Add zabbix-agentd and zabbix-server.</a><span class='msg-avail'>...</span></td><td>Oleg Pykhalov</td></tr>
<tr><td><span title='2018-07-09 10:39:06 +0200'>2018-07-09</span></td><td><a href='/guix/commit/gnu/packages/monitoring.scm?id=a33652ee336ae9a5d2ab5fd54bf2397caec42a0e'>services: Add prometheus-node-exporter-service-type.</a><span class='msg-avail'>...</span></td><td>Gábor Boskovits</td></tr>