Demo: Read a ChemDraw File
Document 0 [0x0000] Creation Program:ChemDraw 126.96.36.1996 Name:benzene.cdx Font Table:Windows fonts: Font[id:20, characterSet: 10000, name: Times],Font[id:21, characterSet: 10000, name: Helvetica] Bounding Box:(10444645t, 6456556r, 14452480b, 9927443l) Color Table:Color[red: 65535, green: 65535, blue: 65535],Color[red: 0, green: 0, blue: 0],Color[red: 65535, green: 0, blue: 0],Color[red: 65535, green: 65535, blue: 0],Color[red: 0, green: 65535, blue: 0],Color[red: 0, green: 65535, blue: 65535],Color[red: 0, green: 0, blue: 65535],Color[red: 65535, green: 0, blue: 65535] Foreground Color:0 Background Color:1 Atom Show Query:true Atom Show Stereo:false Atom Show Atom Number:false Atom Show Terminal Carbon Labels:true Atom Show Non-Terminal Carbon Labels:true Atom Hide Implicit Hydrogens:true Atom Show Enhanced Stereo:true Bond Show Query:true Bond Show Stereo:false Bond Show Reaction:true Interpret Chemically:true Mac Print Info:0,3,0,0,2,208,2,208,0,0,0,0,29,254,22,246,255,134,255,136,30,118,23,112,3,103,5,40,3,252,0,2,0,0,0,72,0,72,0,0,0,0,2,216,2,40,0,1,0,0,0,100,0,0,0,1,0,3,3,3,0,0,0,1,39,15,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,104,0,0,25,1,144,0,0,0,0,0,32,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 Print Margins:(2359296t, 2359296r, 2359296b, 2359296l) Chain Angle:7864320 Bond Spacing:120 Bond Length:1966080 Bold Width:262144 Line Width:65536 Margin Width:131072 Hash Spacing:176896 Label Style:Font Style [id: 21 type: 96 size: 200 color: 3] Caption Style:Font Style [id: 20 type: 0 size: 240 color: 3] Caption Justification:0 Fractional Widths:true Label Justification:5 ? : unknown ? : unknown ? [82a]: unknown Window is Zoomed:true Window Position:(3997696, 4915200) Window Size:(38731776, 50528256) Page 43 [0x002b] Bounding Box:(0t, 0r, 47179366b, 35389440l) Width Pages:1 Height Pages:1 Header Position:2359296 Footer Position:2359296 Print Trim Marks:true Fragment 27 [0x001b] Bounding Box:(10444645t, 6456556r, 14452480b, 9927443l) Node 24 [0x0018] Z Order:1 Position 2D:(6489324, 11465523) Atom CIP Stereochemistry:1 Node End Node 26 [0x001a] Z Order:3 Position 2D:(6489324, 13431603) Atom CIP Stereochemistry:1 Node End Node 28 [0x001c] Z Order:5 Position 2D:(8192000, 14414643) Atom CIP Stereochemistry:1 Node End Node 30 [0x001e] Z Order:7 Position 2D:(9894675, 13431603) Atom CIP Stereochemistry:1 Node End Node 32 [0x0020] Z Order:9 Position 2D:(9894675, 11465523) Atom CIP Stereochemistry:1 Node End Node 34 [0x0022] Z Order:11 Position 2D:(8192000, 10482483) Atom CIP Stereochemistry:1 Node End Bond 36 [0x0024] Z Order:13 Bond Order:2 Bond Double Position:1 Bond Begin:24 Bond End:26 Bond Bond Ordering:41,0,0,37 Bond End Bond 37 [0x0025] Z Order:14 Bond Begin:26 Bond End:28 Bond CIP Stereochemistry:1 Bond End Bond 38 [0x0026] Z Order:15 Bond Order:2 Bond Double Position:1 Bond Begin:28 Bond End:30 Bond Bond Ordering:37,0,0,39 Bond End Bond 39 [0x0027] Z Order:16 Bond Begin:30 Bond End:32 Bond CIP Stereochemistry:1 Bond End Bond 40 [0x0028] Z Order:17 Bond Order:2 Bond Double Position:1 Bond Begin:32 Bond End:34 Bond Bond Ordering:39,0,0,41 Bond End Bond 41 [0x0029] Z Order:18 Bond Begin:34 Bond End:24 Bond CIP Stereochemistry:1 Bond End Fragment End Page End Document End
Being able to visualize the contents of arbitrary CDX files this way is an important aid to debugging and a prerequisite to developing full-featured graphical display capability.
It's a pretty safe bet that any organic chemist who has written a report, submitted a journal manuscript, or filed a patent has used ChemDraw. As a result, ChemDraw files are everywhere in chemistry.
If you've spent any time watching how chemists work, the need to manipulate CDX files may be obvious. Even so, I'd like to offer a specific example taken from a recent project that illustrates that the need to work with CDX files can come from some unlikely places.
These structures and reactions schemes are automatically pre-rendered through AppleScript automation of the ChemDraw application. Although this works, it's far from optimal. For example, Reagents runs on iPad 3 (retina) displays. To prevent pixellation, our horizontal resolution measures in the thousands of pixels. The large size of the resulting images means more storage space and longer download times. But the biggest problem lies in the fact that every time we make changes to these ChemDraw files, we must regenerate the corresponding raster image.
It would be so much better to dynamically render these ChemDraw files inside an iOS UI element such as UIWebView.
We'd also like to do interesting things with the ChemDraw files themselves. I won't spill the beans here, but suffice it to say that if we're successful you'll be seeing one or more new iOS apps that repurpose the Reagents content in some interesting ways.
Given the centrality of the CDX file format in chemistry, we're starting there first.