2020-12-01 17:51:00

1 files changed, 55 insertions, 0 deletions

diff --git a/tex/context/base/mkxl/back-pdf.lmt b/tex/context/base/mkxl/back-pdf.lmt
new file mode 100644
index 000000000..44d0230bd
--- /dev/null
+++ b/tex/context/base/mkxl/back-pdf.lmt
@@ -0,0 +1,55 @@
+if not modules then modules = { } end modules ['back-pdf'] = {
+    version   = 1.001,
+    comment   = "companion to back-pdf.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- We hide the pdf table from users so that we can guarantee no interference with
+-- the way we manage resources, info, etc. Users should use the \type {lpdf}
+-- interface instead. If needed I will provide replacement functionality.
+
+local setmetatableindex = table.setmetatableindex
+
+local pdfsetcompression
+local pdfimmediateobject
+
+updaters.register("backend.update.lpdf",function()
+    pdfsetcompression  = lpdf.setcompression
+    pdfimmediateobject = lpdf.immediateobject
+end)
+
+interfaces.implement {
+    name      = "setpdfcompression",
+    arguments = { "integer", "integer" },
+    actions   = function(...) pdfsetcompression(...) end,
+}
+
+do
+
+    local dummy  = function() end
+    local report = logs.reporter("backend")
+
+    local function unavailable(t,k)
+        report("calling unavailable pdf.%s function",k)
+        t[k] = dummy
+        return dummy
+    end
+
+    updaters.register("backend.update",function()
+        --
+        -- For now we keep this for tikz. If really needed some more can be made
+        -- accessible but it has to happen in a controlled way then, for instance
+        -- by first loading or enabling some compatibility layer so that we can
+        -- trace possible interferences.
+        --
+        pdf = {
+            immediateobj = pdfimmediateobject
+        }
+        setmetatableindex(pdf,unavailable)
+    end)
+
+end
+
+backends.install("pdf")