docs-rst: auto-generate PDF image files

The PDF files that contain media images were actually generated
offline from their SVG or PNG source files.

Sphinx can handle PNG sources automatially. So, let's just
drop their PDF counterparts.

For SVG, however, Sphinx doesn't produce the right tags to
use the TexLive SVG support. Also, the SVG support is done via
shell execution, with is not nice.

So, while we don't have any support for SVG inside Sphinx
core or as an extension, move the logic to build them to Makefile,
producing the PDF images on runtime.

NOTE: due to the way Sphinx works, the PDF images should be
generated inside the Kernel source tree, as otherwise Sphinx
won't find it, not obeying what's specified by "O=" makefile
parameter.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/Makefile.sphinx

@@ -54,7 +54,7 @@ loop_cmd = $(echo-cmd) $(cmd_$(1))
 #    e.g. "media" for the linux-tv book-set at ./Documentation/media
 
 quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
-      cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/media all;\
+      cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/media $2;\
 	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \
 	$(SPHINXBUILD) \
 	-b $2 \
@@ -98,6 +98,7 @@ installmandocs:
 
 cleandocs:
 	$(Q)rm -rf $(BUILDDIR)
+	$(Q)$(MAKE) -C Documentation/media clean
 
 endif # HAVE_SPHINX
 

Documentation/media/.gitignore

@@ -0,0 +1 @@
+*.pdf

Documentation/media/Makefile

@@ -10,8 +10,35 @@ FILES = audio.h.rst ca.h.rst dmx.h.rst frontend.h.rst net.h.rst video.h.rst \
 
 TARGETS := $(addprefix $(BUILDDIR)/, $(FILES))
 
-.PHONY: all
+IMAGES = \
+	typical_media_device.svg \
+	uapi/dvb/dvbstb.svg \
+	uapi/v4l/constraints.svg \
+	uapi/v4l/subdev-image-processing-full.svg \
+	uapi/v4l/subdev-image-processing-scaling-multi-source.svg \
+	uapi/v4l/subdev-image-processing-crop.svg \
+
+IMGTGT := $(patsubst %.png,%.pdf,$(patsubst %.svg,%.pdf,$(IMAGES)))
+IMGPDF := $(patsubst %,$(SRC_DIR)/%,$(IMGTGT))
+
+cmd = $(echo-cmd) $(cmd_$(1))
+
+quiet_cmd_genpdf = GENPDF  $2
+      cmd_genpdf = convert $2 $3
+
+%.pdf: %.svg
+	@$(call cmd,genpdf,$<,$@)
+
+.PHONY: all html epub xml latex
+
 all: $(BUILDDIR) ${TARGETS}
+html: all
+epub: all
+xml: all
+latex: $(IMGPDF) all
+
+clean:
+	-rm $(IMGTGT) 2>/dev/null
 
 $(BUILDDIR):
 	$(Q)mkdir -p $@

Documentation/media/intro.rst

@@ -13,8 +13,8 @@ A typical media device hardware is shown at :ref:`typical_media_device`.
 
 .. _typical_media_device:
 
-.. figure::  media_api_files/typical_media_device.*
-    :alt:    typical_media_device.svg
+.. figure::  typical_media_device.*
+    :alt:    typical_media_device.pdf / typical_media_device.svg
     :align:  center
 
     Typical Media Device

Documentation/media/uapi/dvb/intro.rst

@@ -55,7 +55,7 @@ Overview
 
 .. _stb_components:
 
-.. figure::  intro_files/dvbstb.*
+.. figure::  dvbstb.*
     :alt:    dvbstb.pdf / dvbstb.svg
     :align:  center
 

Documentation/media/uapi/v4l/crop.rst

@@ -53,8 +53,8 @@ Cropping Structures
 
 .. _crop-scale:
 
-.. figure::  crop_files/crop.*
-    :alt:    crop.pdf / crop.gif
+.. figure::  crop.png
+    :alt:    crop.png
     :align:  center
 
     Image Cropping, Insertion and Scaling

Documentation/media/uapi/v4l/dev-raw-vbi.rst

@@ -221,8 +221,8 @@ and always returns default parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does
 
 .. _vbi-hsync:
 
-.. figure::  dev-raw-vbi_files/vbi_hsync.*
-    :alt:    vbi_hsync.pdf / vbi_hsync.gif
+.. figure::  vbi_hsync.png
+    :alt:    vbi_hsync.png
     :align:  center
 
     **Figure 4.1. Line synchronization**
@@ -230,8 +230,8 @@ and always returns default parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does
 
 .. _vbi-525:
 
-.. figure::  dev-raw-vbi_files/vbi_525.*
-    :alt:    vbi_525.pdf / vbi_525.gif
+.. figure::  vbi_525.png
+    :alt:    vbi_525.png
     :align:  center
 
     **Figure 4.2. ITU-R 525 line numbering (M/NTSC and M/PAL)**
@@ -240,8 +240,8 @@ and always returns default parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does
 
 .. _vbi-625:
 
-.. figure::  dev-raw-vbi_files/vbi_625.*
-    :alt:    vbi_625.pdf / vbi_625.gif
+.. figure::  vbi_625.png
+    :alt:    vbi_625.png
     :align:  center
 
     **Figure 4.3. ITU-R 625 line numbering**

Documentation/media/uapi/v4l/dev-subdev.rst

@@ -99,8 +99,8 @@ the video sensor and the host image processing hardware.
 
 .. _pipeline-scaling:
 
-.. figure::  dev-subdev_files/pipeline.*
-    :alt:    pipeline.pdf / pipeline.png
+.. figure::  pipeline.png
+    :alt:    pipeline.png
     :align:  center
 
     Image Format Negotiation on Pipelines
@@ -404,8 +404,8 @@ selection will refer to the sink pad format dimensions instead.
 
 .. _subdev-image-processing-crop:
 
-.. figure::  dev-subdev_files/subdev-image-processing-crop.*
-    :alt:    subdev-image-processing-crop.svg
+.. figure::  subdev-image-processing-crop.*
+    :alt:    subdev-image-processing-crop.pdf / subdev-image-processing-crop.svg
     :align:  center
 
     **Figure 4.5. Image processing in subdevs: simple crop example**
@@ -421,8 +421,8 @@ pad.
 
 .. _subdev-image-processing-scaling-multi-source:
 
-.. figure::  dev-subdev_files/subdev-image-processing-scaling-multi-source.*
-    :alt:    subdev-image-processing-scaling-multi-source.svg
+.. figure::  subdev-image-processing-scaling-multi-source.*
+    :alt:    subdev-image-processing-scaling-multi-source.pdf / subdev-image-processing-scaling-multi-source.svg
     :align:  center
 
     **Figure 4.6. Image processing in subdevs: scaling with multiple sources**
@@ -437,8 +437,8 @@ an area at location specified by the source crop rectangle from it.
 
 .. _subdev-image-processing-full:
 
-.. figure::  dev-subdev_files/subdev-image-processing-full.*
-    :alt:    subdev-image-processing-full.svg
+.. figure::  subdev-image-processing-full.*
+    :alt:    subdev-image-processing-full.pdf / subdev-image-processing-full.svg
     :align:  center
 
     **Figure 4.7. Image processing in subdevs: scaling and composition with multiple sinks and sources**