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 <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/Makefile.sphinx

···
 #    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 \
···
 
 cleandocs:
 	$(Q)rm -rf $(BUILDDIR)
+	$(Q)$(MAKE) -C Documentation/media clean
 
 endif # HAVE_SPHINX
 

Documentation/media/.gitignore

···
+*.pdf

Documentation/media/Makefile

···
 
 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

···
 
 .. _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

···
 
 .. _stb_components:
 
-.. figure::  intro_files/dvbstb.*
+.. figure::  dvbstb.*
     :alt:    dvbstb.pdf / dvbstb.svg
     :align:  center
 

Documentation/media/uapi/v4l/crop.rst

···
 
 .. _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

···
 
 .. _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**
···
 
 .. _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)**
···
 
 .. _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

···
 
 .. _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
···
 
 .. _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**
···
 
 .. _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**
···
 
 .. _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**

Documentation/media/uapi/v4l/field-order.rst

···
 Field Order, Top Field First Transmitted
 ========================================
 
-.. figure::  field-order_files/fieldseq_tb.*
-    :alt:    fieldseq_tb.pdf / fieldseq_tb.gif
+.. figure::  fieldseq_tb.png
+    :alt:    fieldseq_tb.png
     :align:  center
 
 
···
 Field Order, Bottom Field First Transmitted
 ===========================================
 
-.. figure::  field-order_files/fieldseq_bt.*
-    :alt:    fieldseq_bt.pdf / fieldseq_bt.gif
+.. figure::  fieldseq_bt.png
+    :alt:    fieldseq_bt.png
     :align:  center
 

Documentation/media/uapi/v4l/pixfmt-nv12mt.rst

···
 
 .. _nv12mt:
 
-.. figure::  pixfmt-nv12mt_files/nv12mt.*
+.. figure::  nv12mt.png
     :alt:    nv12mt.png
     :align:  center
 
···
 
 .. _nv12mt_ex:
 
-.. figure::  pixfmt-nv12mt_files/nv12mt_example.*
+.. figure::  nv12mt_example.png
     :alt:    nv12mt_example.png
     :align:  center
 

Documentation/media/uapi/v4l/selection-api-003.rst

···
 
 .. _sel-targets-capture:
 
-.. figure::  selection-api-003_files/selection.*
+.. figure::  selection.png
     :alt:    selection.png
     :align:  center
 

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

···
 
 .. _bayer-patterns:
 
-.. figure::  subdev-formats_files/bayer.*
+.. figure::  bayer.png
     :alt:    bayer.png
     :align:  center
 
     **Figure 4.8 Bayer Patterns**
-
-
 
 The following table lists existing packed Bayer formats. The data
 organization is given as an example for the first pixel only.

Documentation/media/uapi/v4l/vidioc-g-selection.rst

···
 
 .. _sel-const-adjust:
 
-.. figure::  vidioc-g-selection_files/constraints.*
-    :alt:    constraints.svg
+.. figure::  constraints.*
+    :alt:    constraints.pdf / constraints.svg
     :align:  center
 
     Size adjustments with constraint flags.