2018-10-17 15:14:00

1 files changed, 1061 insertions, 0 deletions

diff --git a/tex/context/base/mkiv/lpdf-img.lua b/tex/context/base/mkiv/lpdf-img.lua
new file mode 100644
index 000000000..28890887a
--- /dev/null
+++ b/tex/context/base/mkiv/lpdf-img.lua
@@ -0,0 +1,1061 @@
+if not modules then modules = { } end modules ['lpdf-img'] = {
+    version   = 1.001,
+    comment   = "companion to lpdf-ini.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local concat, remove, insert = table.concat, table.remove, table.insert
+local ceil = math.ceil
+local char, find = string.char, string.find
+local idiv = number.idiv
+local band, rshift = bit32.band, bit32.rshift
+
+local loaddata             = io.loaddata
+local setmetatableindex    = table.setmetatableindex
+
+local streams              = utilities.streams
+local openstring           = streams.openstring
+local readstring           = streams.readstring
+local readbytetable        = streams.readbytetable
+
+local lpdf                 = lpdf or { }
+local pdfdictionary        = lpdf.dictionary
+local pdfarray             = lpdf.array
+local pdfconstant          = lpdf.constant
+local pdfstring            = lpdf.string
+local pdfflushstreamobject = lpdf.flushstreamobject
+local pdfreference         = lpdf.reference
+
+local pdfmajorversion      = lpdf.majorversion
+local pdfminorversion      = lpdf.minorversion
+
+local newimage             = img.new
+
+local trace                = false
+
+local report_jpg           = logs.reporter("graphics","jpg")
+local report_jp2           = logs.reporter("graphics","jp2")
+local report_png           = logs.reporter("graphics","png")
+
+local injectors = { }
+lpdf.injectors  = injectors
+
+local chars = setmetatableindex(function(t,k) -- share this one
+    local v = (k <= 0 and "\000") or (k >= 255 and "\255") or char(k)
+    t[k] = v
+    return v
+end)
+
+do
+
+    function injectors.jpg(specification)
+        if specification.error then
+            return
+        end
+        local filename = specification.filename
+        if not filename then
+            return
+        end
+        local colorspace  = specification.colorspace or jpg_gray
+        local attributes  = specification.attr
+        local decodearray = nil
+        ----- procset     = colorspace == 0 and "image b" or "image c"
+        if colorspace == 1 then
+            colorspace = "DeviceGray"
+        elseif colorspace == 2 then
+            colorspace = "DeviceRGB"
+        elseif colorspace == 3 then
+            colorspace  = "DeviceCMYK"
+            decodearray = pdfarray { 1, 0, 1, 0, 1, 0, 1, 0 }
+        end
+        -- todo: set filename
+        local xsize      = specification.xsize
+        local ysize      = specification.ysize
+        local colordepth = specification.colordepth
+        local content    = loaddata(filename)
+        local xobject    = pdfdictionary {
+            Type             = pdfconstant("XObject"),
+            Subtype          = pdfconstant("Image"),
+            BBox             = pdfarray { 0, 0, xsize, ysize },
+            Width            = xsize,
+            Height           = ysize,
+            BitsPerComponent = colordepth,
+            Filter           = pdfconstant("DCTDecode"),
+            ColorSpace       = pdfconstant(colorspace),
+            Decode           = decodearray,
+            Length           = #content, -- specification.length
+        }
+        if attributes then
+            -- todo: add attributes to d
+        end
+        if trace then
+            report_jpg("%s: width %i, height %i, colordepth %i, size %i",filename,xsize,ysize,colordepth,#content)
+        end
+        return newimage {
+            bbox     = { 0, 0, specification.width/xsize, specification.height/ysize }, -- mandate
+            nolength = true,
+            nobbox   = true,
+            notype   = true,
+            stream   = content,
+            attr     = xobject(),
+        }
+    end
+
+end
+
+do
+
+    function injectors.jp2(specification)
+        if specification.error then
+            return
+        end
+        local filename = specification.filename
+        if not filename then
+            return
+        end
+        local attributes  = specification.attr
+        -- todo: set filename
+        local xsize   = specification.xsize
+        local ysize   = specification.ysize
+        local content = loaddata(filename)
+        local xobject = pdfdictionary {
+            Type    = pdfconstant("XObject"),
+            Subtype = pdfconstant("Image"),
+            BBox    = pdfarray { 0, 0, xsize, ysize },
+            Width   = xsize,
+            Height  = ysize,
+            Filter  = pdfconstant("JPXDecode"),
+            Length  = #content, -- specification.length
+        }
+        if attributes then
+            -- todo: add attributes to d
+        end
+        if trace then
+            report_jp2("%s: width %i, height %i, size %i",filename,xsize,ysize,#content)
+        end
+        return newimage {
+            bbox     = { 0, 0, specification.width/xsize, specification.height/ysize }, -- mandate
+            nolength = true,
+            nobbox   = true,
+            notype   = true,
+            stream   = content,
+            attr     = xobject(),
+        }
+    end
+
+end
+
+do
+
+    -- We don't like interlaced files. You can deinterlace them beforehand because otherwise
+    -- each run you add runtime. Actually, even masked images can best be converted to PDF
+    -- beforehand.
+
+    -- The amount of code is larger that I like and looks somewhat redundant but we sort of
+    -- optimize a few combinations that happen often.
+
+    local function convert(t,len)
+        if len then
+local n = 0
+            for i=1,#t,len do
+                t[i] = ""
+n = n + 1
+            end
+        end
+        for i=1,#t do
+            local ti = t[i]
+            if ti ~= "" then
+                t[i] = chars[ti]
+            end
+        end
+        return concat(t)
+    end
+
+    local function zero(t,k)
+        return 0
+    end
+
+    local function bump(txt,t,xsize,ysize,bpp)
+        local l = xsize * bpp + 1
+        print(txt,">",xsize,ysize,bpp,l)
+        for i=1,ysize do
+            local f = (i-1) * l + 1
+            print(txt,i,":",concat(t," ",f,f+l-1))
+        end
+    end
+
+    local function decodeall(t,xsize,ysize,bpp)
+        local len  = xsize * bpp + 1
+        local n    = 1
+        local m    = len - 1
+        for i=1,ysize do
+            local filter = t[n]
+t[n] = 0 -- not needed
+            if filter == 0 then
+            elseif filter == 1 then
+                for j=n+bpp+1,n+m do
+                    t[j] = (t[j] + t[j-bpp]) % 256
+                end
+            elseif filter == 2 then
+                for j=n+1,n+m do
+                    t[j] = (t[j] + t[j-len]) % 256
+                end
+            elseif filter == 3 then
+                for j=n+1,n+bpp do
+                    t[j] = (t[j] + idiv(t[j-len],2)) % 256
+                end
+                for j=n+bpp+1,n+m do
+                    t[j] = (t[j] + idiv(t[j-bpp] + t[j-len],2)) % 256
+                end
+            elseif filter == 4 then
+                for j=n+1,n+bpp do
+                    local p = j - len
+                    local b = t[p]
+                    if b < 0 then
+                        b = - b
+                    end
+                    if b > 0 then
+                        t[j] = (t[j] + b) % 256
+                    end
+                end
+                for j=n+bpp+1,n+m do
+                    local p = j - len
+                    local a = t[j-bpp]
+                    local b = t[p]
+                    local c = t[p-bpp]
+                    local pa = b - c
+                    local pb = a - c
+                    local pc = pa + pb
+                    if pa < 0 then pa = - pa end
+                    if pb < 0 then pb = - pb end
+                    if pc < 0 then pc = - pc end
+                    t[j] = (t[j] + ((pa <= pb and pa <= pc and a) or (pb <= pc and b) or c)) % 256
+                end
+            end
+            n = n + len
+        end
+    end
+
+    local xstart = { 0, 4, 0, 2, 0, 1, 0 }
+    local xstep  = { 8, 8, 4, 4, 2, 2, 1 }
+    local ystart = { 0, 0, 4, 0, 2, 0, 1 }
+    local ystep  = { 8, 8, 8, 4, 4, 2, 2 }
+    ----- xmax   = { 8, 4, 4, 2, 2, 1, 1 } -- for block fill
+    ----- ymax   = { 8, 8, 4, 4, 2, 2, 1 } -- for block fill
+
+    local function newoutput(width,height)
+        local t = { }
+        for i=1,height*width do
+            t[i] = 0
+        end
+        return t
+    end
+
+    local function expand(t,xsize,ysize,parts,factor) -- we don't compact
+        local o = { }
+        local k = 0
+        local l = ceil(xsize*parts/8) + 1
+        local n = 1
+        if factor then
+            if parts == 4 then
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,4),0x0F) * 0x11 ; k = k + 1 ; o[k] = band(rshift(v,0),0x0F) * 0x11
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            elseif parts == 2 then
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,6),0x03) * 0x55 ; k = k + 1 ; o[k] = band(rshift(v,4),0x03) * 0x55
+                        k = k + 1 ; o[k] = band(rshift(v,2),0x03) * 0x55 ; k = k + 1 ; o[k] = band(rshift(v,0),0x03) * 0x55
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            else
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,7),0x01) * 0xFF ; k = k + 1 ; o[k] = band(rshift(v,6),0x01) * 0xFF
+                        k = k + 1 ; o[k] = band(rshift(v,5),0x01) * 0xFF ; k = k + 1 ; o[k] = band(rshift(v,4),0x01) * 0xFF
+                        k = k + 1 ; o[k] = band(rshift(v,3),0x01) * 0xFF ; k = k + 1 ; o[k] = band(rshift(v,2),0x01) * 0xFF
+                        k = k + 1 ; o[k] = band(rshift(v,1),0x01) * 0xFF ; k = k + 1 ; o[k] = band(rshift(v,0),0x01) * 0xFF
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            end
+        else
+            if parts == 4 then
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,4),0x0F) ; k = k + 1 ; o[k] = band(rshift(v,0),0x0F)
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            elseif parts == 2 then
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,6),0x03) ; k = k + 1 ; o[k] = band(rshift(v,4),0x03)
+                        k = k + 1 ; o[k] = band(rshift(v,2),0x03) ; k = k + 1 ; o[k] = band(rshift(v,0),0x03)
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            else
+                for i=1,ysize do
+                    k = k + 1 ; o[k] = t[n]
+                    for j=n+1,n+l do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = band(rshift(v,7),0x01) ; k = k + 1 ; o[k] = band(rshift(v,6),0x01)
+                        k = k + 1 ; o[k] = band(rshift(v,5),0x01) ; k = k + 1 ; o[k] = band(rshift(v,4),0x01)
+                        k = k + 1 ; o[k] = band(rshift(v,3),0x01) ; k = k + 1 ; o[k] = band(rshift(v,2),0x01)
+                        k = k + 1 ; o[k] = band(rshift(v,1),0x01) ; k = k + 1 ; o[k] = band(rshift(v,0),0x01)
+                    end
+                    k = i * (xsize + 1)
+                    n = n + l
+                end
+            end
+        end
+        for i=#o,k+1,-1 do
+            o[i] = nil
+        end
+        return o
+    end
+
+    local function deinterlaceXX(s,xsize,ysize,bytes,parts,factor)
+        local output = newoutput(xsize*bytes,ysize)
+        for pass=1,7 do
+            local ystart = ystart[pass]
+            local ystep  = ystep[pass]
+            local xstart = xstart[pass]
+            local xstep  = xstep[pass]
+            local nx     = idiv(xsize + xstep - xstart - 1,xstep)
+            local ny     = idiv(ysize + ystep - ystart - 1,ystep)
+            if nx > 0 and ny > 0 then
+                local input
+                if parts then
+                    local nxx = ceil(nx*parts/8)
+                    input = readbytetable(s,ny*(nxx+1))
+                    setmetatableindex(input,zero)
+                    decodeall(input,nxx,ny,bytes)
+                    input = expand(input,nx,ny,parts,factor)
+                else
+                    input = readbytetable(s,ny*(nx*bytes+1))
+                    setmetatableindex(input,zero)
+                    decodeall(input,nx,ny,bytes)
+                end
+                local l = nx*bytes + 1
+                for i=ny,1,-1 do
+                    remove(input,(i-1)*l+1)
+                end
+                local xstep  = xstep * bytes
+                local xstart = xstart * bytes
+                local xsize  = xsize * bytes
+                local target = ystart * xsize + xstart + 1
+                local ystep  = ystep * xsize
+                local start  = 1
+                local blobs  = bytes - 1
+                for j=0,ny-1 do
+                    local target = target + j * ystep
+                    for i=1,nx do
+                        for i=0,blobs do
+                            output[target+i] = input[start]
+                            start= start + 1
+                        end
+                        target = target + xstep
+                    end
+                end
+            end
+        end
+        return output
+    end
+
+    local function deinterlaceYY(s,xsize,ysize,bytes,parts,factor)
+        local input
+        if parts then
+            local nxx = ceil(xsize*parts/8)
+            input = readbytetable(s,ysize*(nxx+1))
+            setmetatableindex(input,zero)
+            decodeall(input,nxx,ysize,bytes)
+            input = expand(input,xsize,ysize,parts,factor)
+        else
+            input = readbytetable(s,ysize*(xsize*bytes+1))
+            setmetatableindex(input,zero)
+            decodeall(input,xsize,ysize,bytes)
+        end
+        local l = xsize*bytes + 1
+        local n = 1
+        for i=1,ysize do
+            input[n] = ""
+            n = n + l
+        end
+        return input
+    end
+
+    local function analyze(colordepth,colorspace,palette,mask)
+        local bytes, parts, factor
+        if palette then
+            if colordepth == 16 then
+                return 2, false, false
+            elseif colordepth == 8 then
+                return 1, false, false
+            elseif colordepth == 4 then
+                return 1, 4, false
+            elseif colordepth == 2 then
+                return 1, 2, false
+            elseif colordepth == 1 then
+                return 1, 1, false
+            end
+        elseif colorspace == "DeviceGray" then
+            if colordepth == 16 then
+                return mask and 4 or 2, false, false
+            elseif colordepth == 8 then
+                return mask and 2 or 1, false, false
+            elseif colordepth == 4 then
+                return 1, 4, true
+            elseif colordepth == 2 then
+                return 1, 2, true
+            elseif colordepth == 1 then
+                return 1, 1, true
+            end
+        else
+            if colordepth == 16 then
+                return mask and 8 or 6, false, false
+            elseif colordepth == 8 then
+                return mask and 4 or 3, false, false
+            elseif colordepth == 4 then
+                return 3, 4, true
+            elseif colordepth == 2 then
+                return 3, 2, true
+            elseif colordepth == 1 then
+                return 3, 1, true
+            end
+        end
+        return false, false, false
+    end
+
+    local function deinterlace(content,xsize,ysize,colordepth,colorspace,palette,mask)
+        local bytes, parts, factor = analyze(colordepth,colorspace,palette,mask)
+        if bytes then
+            content = zlib.decompress(content)
+            local s = openstring(content)
+            local r = deinterlaceXX(s,xsize,ysize,bytes,parts,factor)
+            return r, parts and 8 or false
+        end
+    end
+
+    local function decompose(content,xsize,ysize,colordepth,colorspace,palette,mask)
+        local bytes, parts, factor = analyze(colordepth,colorspace,palette,mask)
+        if bytes then
+            content = zlib.decompress(content)
+            local s = openstring(content)
+            local r = deinterlaceYY(s,xsize,ysize,bytes,parts,factor)
+            return r, parts and 8 or false
+        end
+    end
+
+    -- 1 (palette used), 2 (color used), and 4 (alpha channel used)
+
+    -- paeth:
+    --
+    -- p  = a + b - c
+    -- pa = abs(p - a) => a + b - c - a => b - c
+    -- pb = abs(p - b) => a + b - c - b => a - c
+    -- pc = abs(p - c) => a + b - c - c => a + b - c - c => a - c + b - c => pa + pb
+
+    local function prepareimage(content,xsize,ysize,depth,colorspace,mask)
+        local bpp = (depth == 16 and 2 or 1) * ((colorspace == "DeviceRGB" and 3 or 1) + mask)        local len = bpp * xsize + 1
+        local s   = openstring(content)
+        local t   = readbytetable(s,#content)
+        setmetatableindex(t,zero)
+        return t, bpp, len
+    end
+
+    local function filtermask08(xsize,ysize,t,bpp,len,n)
+        local mask = { }
+        local l = 0
+        local m = len - n
+        for i=1,ysize do
+            for j=n+bpp,n+m,bpp do
+                l = l + 1 ; mask[l] = chars[t[j]] ; t[j] = ""
+            end
+            n = n + len
+        end
+        return concat(mask)
+    end
+
+    local function filtermask16(xsize,ysize,t,bpp,len,n)
+        local mask = { }
+        local l = 0
+        local m = len - n
+        for i=1,ysize do
+            for j=n+bpp-1,n+m-1,bpp do
+                l = l + 1 ; mask[l] = chars[t[j]] ; t[j] = ""
+                j = j + 1
+                l = l + 1 ; mask[l] = chars[t[j]] ; t[j] = ""
+            end
+            n = n + len
+        end
+        return concat(mask)
+    end
+
+    local function decodemask08(content,xsize,ysize,depth,colorspace)
+        local t, bpp, len = prepareimage(content,xsize,ysize,depth,colorspace,1)
+        local bpp2 = mask and (bpp + bpp) or bpp
+        local n = 1
+        local m = len - 1
+        for i=1,ysize do
+            local filter = t[n]
+            if filter == 0 then
+            elseif filter == 1 then
+                for j=n+bpp2,n+m,bpp do
+                    t[j] = (t[j] + t[j-bpp]) % 256
+                end
+            elseif filter == 2 then
+                for j=n+bpp,n+m,bpp do
+                    t[j] = (t[j] + t[j-len]) % 256
+                end
+            elseif filter == 3 then
+                local j = n + bpp
+                t[j] = (t[j] + idiv(t[j-len],2)) % 256
+                for j=n+bpp2,n+m,bpp do
+                    t[j] = (t[j] + idiv(t[j-bpp] + t[j-len],2)) % 256
+                end
+            elseif filter == 4 then
+                local j = n + bpp
+                local p = j - len
+                local b = t[p]
+                if b < 0 then
+                    b = - b
+                end
+                if b > 0 then
+                    t[j] = (t[j] + b) % 256
+                end
+                for j=n+bpp2,n+m,bpp do
+                    local p = j - len
+                    local a = t[j-bpp]
+                    local b = t[p]
+                    local c = t[p-bpp]
+                    local pa = b - c
+                    local pb = a - c
+                    local pc = pa + pb
+                    if pa < 0 then pa = - pa end
+                    if pb < 0 then pb = - pb end
+                    if pc < 0 then pc = - pc end
+                    t[j] = (t[j] + ((pa <= pb and pa <= pc and a) or (pb <= pc and b) or c)) % 256
+                end
+            end
+            n = n + len
+        end
+        local mask = filtermask08(xsize,ysize,t,bpp,len,1)
+        return convert(t), mask
+    end
+
+    local function decodemask16(content,xsize,ysize,depth,colorspace)
+        local t, bpp, len = prepareimage(content,xsize,ysize,depth,colorspace,1)
+        local bpp2 = bpp + bpp
+        local n = 1
+        local m = len - 1
+        for i=1,ysize do
+            local filter = t[n]
+            if filter == 0 then
+            elseif filter == 1 then
+                for j=n+bpp2,n+m,bpp do
+                    local k = j - 1
+                    t[j] = (t[j] + t[j-bpp]) % 256
+                    t[k] = (t[k] + t[k-bpp]) % 256
+                end
+            elseif filter == 2 then
+                for j=n+bpp,n+m,bpp do
+                    local k = j - 1
+                    t[j] = (t[j] + t[j-len]) % 256
+                    t[k] = (t[k] + t[k-len]) % 256
+                end
+            elseif filter == 3 then
+                local j = n + bpp
+                local k = j - 1
+                t[j] = (t[j] + idiv(t[j-len],2)) % 256
+                t[k] = (t[k] + idiv(t[k-len],2)) % 256
+                for j=n+bpp2,n+m,bpp do
+                    local k = j - 1
+                    t[j] = (t[j] + idiv(t[j-bpp] + t[j-len],2)) % 256
+                    t[k] = (t[k] + idiv(t[k-bpp] + t[k-len],2)) % 256
+                end
+            elseif filter == 4 then
+                for i=-1,0 do
+                    local j = n + bpp + i
+                    local p = j - len
+                    local b = t[p]
+                    if b < 0 then
+                        b = - b
+                    end
+                    if b > 0 then
+                        t[j] = (t[j] + b) % 256
+                    end
+                    for j=n+i+bpp2,n+i+m,bpp do
+                        local p = j - len
+                        local a = t[j-bpp]
+                        local b = t[p]
+                        local c = t[p-bpp]
+                        local pa = b - c
+                        local pb = a - c
+                        local pc = pa + pb
+                        if pa < 0 then pa = - pa end
+                        if pb < 0 then pb = - pb end
+                        if pc < 0 then pc = - pc end
+                        t[j] = (t[j] + ((pa <= pb and pa <= pc and a) or (pb <= pc and b) or c)) % 256
+                    end
+                end
+            end
+            n = n + len
+        end
+        local mask = filtermask16(xsize,ysize,t,bpp,len,1)
+        return convert(t), mask
+    end
+
+    local function full(t,k) local v = "\xFF" t[k] = v return v end
+
+    local function create(content,palette,transparent,xsize,ysize,colordepth,colorspace)
+        if palette then
+            --
+            local s = openstring(transparent)
+            local n = #transparent
+            local r = { }
+            for i=0,n-1 do
+                r[i] = readstring(s,1)
+            end
+            setmetatableindex(r,full)
+            --
+            local c = zlib.decompress(content)
+            local s = openstring(c)
+            --
+            local o = { }
+            local len = ceil(xsize*colordepth/8) + 1
+            local m = len - 1
+            local u = setmetatableindex(zero)
+            --
+            for i=1,ysize do
+                local t = readbytetable(s,len)
+                local k = (i-1) * xsize
+                local filter = t[1]
+                if filter == 0 then
+                elseif filter == 1 then
+                    for j=3,len do
+                        t[j] = (t[j] + t[j-1]) % 256
+                    end
+                elseif filter == 2 then
+                    for j=2,len do
+                        t[j] = (t[j] + u[j]) % 256
+                    end
+                elseif filter == 3 then
+                    local j = 2
+                    t[j] = (t[j] + idiv(u[j],2)) % 256
+                    for j=3,len do
+                        t[j] = (t[j] + idiv(t[j-1] + u[j],2)) % 256
+                    end
+                elseif filter == 4 then
+                    local j = 2
+                    local p = j - len
+                    local b = t[p]
+                    if b < 0 then
+                        b = - b
+                    end
+                    if b > 0 then
+                        t[j] = (t[j] + b) % 256
+                    end
+                    for j=3,len do
+                        local p = j - len
+                        local a = t[j-1]
+                        local b = t[p]
+                        local c = t[p-1]
+                        local pa = b - c
+                        local pb = a - c
+                        local pc = pa + pb
+                        if pa < 0 then pa = - pa end
+                        if pb < 0 then pb = - pb end
+                        if pc < 0 then pc = - pc end
+                        t[j] = (t[j] + ((pa <= pb and pa <= pc and a) or (pb <= pc and b) or c)) % 256
+                    end
+                end
+                if colordepth == 8 then
+                    for j=2,len do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = r[v] or "\xFF"
+                    end
+                elseif colordepth == 4 then
+                    for j=2,len do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = r[band(rshift(v,4),0x0F)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,0),0x0F)]
+                    end
+                elseif colordepth == 2 then
+                    for j=2,len do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = r[band(rshift(v,6),0x03)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,4),0x03)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,2),0x03)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,0),0x03)]
+                    end
+                else
+                    for j=2,len do
+                        local v = t[j]
+                        k = k + 1 ; o[k] = r[band(rshift(v,7),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,6),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,5),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,4),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,3),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,2),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,2),0x01)]
+                        k = k + 1 ; o[k] = r[band(rshift(v,1),0x01)]
+                    end
+                end
+                u = t
+            end
+            return concat(o,"",1,ysize * xsize)
+        end
+    end
+
+    local alwaysdecode = false
+
+    directives.register("graphics.png.decode", function(v)
+        alwaysdecode = v
+    end)
+
+    function injectors.png(specification)
+        if specification.error then
+            return
+        end
+        local filename = specification.filename
+        if not filename then
+            return
+        end
+        local colorspace = specification.colorspace
+        if not colorspace then
+            return
+        end
+        local interlace = specification.interlace or 0
+        if interlace == 1 then
+            interlace = true
+        elseif interlace == 0 then
+            interlace = false
+        else
+            report_png("unknown interlacing %i",interlace)
+            return
+        end
+        local tables = specification.tables
+        if not tables then
+            return
+        end
+        local idat = tables.idat
+        if not idat then
+            return
+        end
+        local pngfile = io.open(filename,"rb")
+        if not pngfile then
+            return
+        end
+        local content = idat(pngfile,true)
+        tables.idat = false
+        --
+     -- if tables.gama then
+     --     report_png("ignoring gamma correction")
+     -- end
+        --
+        local xsize       = specification.xsize
+        local ysize       = specification.ysize
+        local colordepth  = specification.colordepth or 8
+        local mask        = false
+        local transparent = false
+        local palette     = false
+        local colors      = 1
+        if     colorspace == 0 then    -- gray | image b
+            colorspace  = "DeviceGray"
+            transparent = true
+        elseif colorspace == 2 then    -- rgb | image c
+            colorspace  = "DeviceRGB"
+            colors      = 3
+            transparent = true
+        elseif colorspace == 3 then    -- palette | image c+i
+            colorspace  = "DeviceRGB"
+            palette     = true
+            transparent = true
+        elseif colorspace == 4 then    -- gray | alpha | image b
+            colorspace = "DeviceGray"
+            mask       = true
+        elseif colorspace == 6 then    -- rgb | alpha | image c
+            colorspace = "DeviceRGB"
+            colors     = 3
+            mask       = true
+        else
+            report_png("unknown colorspace %i",colorspace)
+            return
+        end
+        --
+        if transparent then
+            local trns = tables.trns
+            if trns then
+                transparent = trns(pngfile,true)
+                if transparent == "" then
+                    transparent = false
+                end
+                tables.trns = false
+            else
+                transparent = false
+            end
+        end
+        --
+        local decode = alwaysdecode
+        local major  = pdfmajorversion()
+        local minor  = pdfminorversion()
+        if major > 1 then
+            -- we're okay
+        elseif minor < 5 and colordepth == 16 then
+            report_png("16 bit colordepth not supported in pdf < 1.5")
+            return
+        elseif minor < 4 and (mask or transparent) then
+            report_png("alpha channels not supported in pdf < 1.4")
+            return
+        elseif minor < 2 then
+            decode = true
+        end
+        --
+        -- todo: compresslevel (or delegate)
+        --
+        if palette then
+            local plte = tables.plte
+            if plte then
+                palette = plte(pngfile,true)
+                if palette == "" then
+                    palette = false
+                end
+                tables.plte = false
+            else
+                palette = false
+            end
+        end
+        --
+        if interlace then
+            local r, p = deinterlace(content,xsize,ysize,colordepth,colorspace,palette,mask)
+            if not r then
+                return
+            end
+            if p then
+                colordepth = p
+            end
+            if mask then
+                local bpp = (colordepth == 16 and 2 or 1) * ((colorspace == "DeviceRGB" and 3 or 1) + 1)
+                local len = bpp * xsize -- + 1
+                if colordepth == 8 then -- bpp == 1
+                    mask = filtermask08(xsize,ysize,r,bpp,len,0)
+                elseif colordepth == 16 then -- bpp == 2
+                    mask = filtermask16(xsize,ysize,r,bpp,len,0)
+                else
+                    report_png("mask can't be split from the image")
+                    return
+                end
+            end
+            decode  = true
+            content = convert(r)
+            content = zlib.compress(content)
+        elseif mask then
+            local decoder
+            if colordepth == 8 then
+                decoder = decodemask08
+            elseif colordepth == 16 then
+                decoder = decodemask16
+            end
+            if not decoder then
+                report_png("mask can't be split from the image")
+                return
+            end
+            content = zlib.decompress(content)
+            content, mask = decoder(content,xsize,ysize,colordepth,colorspace)
+            content = zlib.compress(content)
+            decode  = false
+        elseif transparent then
+            if palette then
+                mask = create(content,palette,transparent,xsize,ysize,colordepth,colorspace)
+            else
+                pallette = false
+            end
+        elseif decode then
+            local r, p = decompose(content,xsize,ysize,colordepth,colorspace,palette)
+            if not r then
+                return
+            end
+            if p then
+                colordepth = p
+            end
+            content = convert(r)
+            content = zlib.compress(content)
+        end
+        if palette then
+            palette = pdfarray {
+                pdfconstant("Indexed"),
+                pdfconstant("DeviceRGB"),
+                idiv(#palette,3),
+                pdfreference(pdfflushstreamobject(palette)),
+            }
+        end
+        pngfile:close()
+        local xobject = pdfdictionary {
+            Type             = pdfconstant("XObject"),
+            Subtype          = pdfconstant("Image"),
+            BBox             = pdfarray { 0, 0, xsize, ysize },
+            Width            = xsize,
+            Height           = ysize,
+            BitsPerComponent = colordepth,
+            Filter           = pdfconstant("FlateDecode"),
+            ColorSpace       = palette or pdfconstant(colorspace),
+            Length           = #content,
+        }
+        if mask then
+            local d = pdfdictionary {
+                Type             = pdfconstant("XObject"),
+                Subtype          = pdfconstant("Image"),
+                Width            = xsize,
+                Height           = ysize,
+                BitsPerComponent = palette and 8 or colordepth,
+                ColorSpace       = pdfconstant("DeviceGray"),
+            }
+            xobject.SMask = pdfreference(pdfflushstreamobject(mask,d()))
+        end
+        if not decode then
+            xobject.DecodeParms  = pdfdictionary {
+                Colors           = colors,
+                Columns          = xsize,
+                BitsPerComponent = colordepth,
+                Predictor        = 15,
+            }
+        end
+        if attributes then
+            -- todo: add attributes to d
+        end
+        if trace then
+            report_png("%s: width %i, height %i, colordepth: %i, size: %i, palette %l, mask: %l, transparent %l, decode %l",filename,xsize,ysize,colordepth,#content,palette,mask,transparent,decode)
+        end
+        return newimage {
+            bbox     = { 0, 0, specification.width/xsize, specification.height/ysize }, -- mandate
+            nolength = true,
+            nobbox   = true,
+            notype   = true,
+            stream   = content,
+            attr     = xobject(),
+        }
+    end
+
+end
+
+do
+
+    local function pack(specification,what)
+        local t = { }
+        local n = 0
+        local s = specification.colorspace
+        local d = specification.data
+        local x = specification.xsize
+        local y = specification.ysize
+        if what == "mask" then
+            d = specification.mask
+            s = 1
+        end
+        if s == 1 then
+            for i=1,y do
+                local r = d[i]
+                for j=1,x do
+                    n = n + 1 ; t[n] = chars[r[j]]
+                end
+            end
+        elseif s == 2 then
+            for i=1,y do
+                local r = d[i]
+                for j=1,x do
+                    local c = r[j]
+                    n = n + 1 ; t[n] = chars[c[1]]
+                    n = n + 1 ; t[n] = chars[c[2]]
+                    n = n + 1 ; t[n] = chars[c[3]]
+                end
+            end
+        elseif s == 3 then
+            for i=1,y do
+                local r = d[i]
+                for j=1,x do
+                    local c = r[j]
+                    n = n + 1 ; t[n] = chars[c[1]]
+                    n = n + 1 ; t[n] = chars[c[2]]
+                    n = n + 1 ; t[n] = chars[c[3]]
+                    n = n + 1 ; t[n] = chars[c[4]]
+                end
+            end
+        end
+        return concat(t)
+    end
+
+    function injectors.bitmap(specification)
+        local data = specification.data
+        if not data then
+            return
+        end
+        local xsize = specification.xsize or 0
+        local ysize = specification.ysize or 0
+        if xsize == 0 or ysize == 0 then
+            return
+        end
+        local colorspace = specification.colorspace or 1
+        if colorspace == 1 then
+            colorspace = "DeviceGray"
+        elseif colorspace == 2 then
+            colorspace = "DeviceRGB"
+        elseif colorspace == 3 then
+            colorspace  = "DeviceCMYK"
+        end
+        local colordepth = (specification.colordepth or 2) == 16 or 8
+        local content    = pack(specification,"data")
+        local mask       = specification.mask
+        local xobject    = pdfdictionary {
+            Type             = pdfconstant("XObject"),
+            Subtype          = pdfconstant("Image"),
+            BBox             = pdfarray { 0, 0, xsize, ysize },
+            Width            = xsize,
+            Height           = ysize,
+            BitsPerComponent = colordepth,
+            ColorSpace       = pdfconstant(colorspace),
+            Length           = #content, -- specification.length
+        }
+        if mask then
+            local d = pdfdictionary {
+                Type             = pdfconstant("XObject"),
+                Subtype          = pdfconstant("Image"),
+                Width            = xsize,
+                Height           = ysize,
+                BitsPerComponent = colordepth,
+                ColorSpace       = pdfconstant("DeviceGray"),
+            }
+            xobject.SMask = pdfreference(pdfflushstreamobject(pack(specification,"mask"),d()))
+        end
+        return newimage {
+            bbox     = { 0, 0, specification.width/xsize, specification.height/ysize }, -- mandate
+         -- nolength = true,
+            nobbox   = true,
+            notype   = true,
+            stream   = content,
+            attr     = xobject(),
+        }
+    end
+
+end