Graphics

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Problem with image dimensions being reversed Alan Burkhart29-Jul-09 9:38 Alan Burkhart 29-Jul-09 9:38  I've built a utility that grabs the frames from a multi-frame .tif or gif so I can save them to individual files. In one file (a tif fax document) the dimensions are reversed - 11 x 8.5 instead of 8.5 by 11. Text orientation is correct, but not the dimensions. I assume the problem is on my end because when I open the file in Irfanview it displays correctly. None of the other TIFs I'm testing with are fax documents, and they display correctly. Worth noting that both Paint.net and MS Paint have the same problem I'm having. Anyone have an idea as to the root of the problem? repost Luc Pattyn31-Jul-09 18:56 Luc Pattyn 31-Jul-09 18:56  http://www.codeproject.com/Messages/3140205/Problem-with-image-dimensions-being-reversed.aspx[^] Luc Pattyn [Forum Guidelines] [My Articles] The quality and detail of your question reflects on the effectiveness of the help you are likely to get. Show formatted code inside PRE tags, and give clear symptoms when describing a problem. jawbreaker in c++ sajede27-Jul-09 18:14 sajede 27-Jul-09 18:14  hi, please help me to wrtie code project of jawbreaker game in c++. Re: jawbreaker in c++ Tim Craig27-Jul-09 18:34 Tim Craig 27-Jul-09 18:34  Why? You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists. Re: jawbreaker in c++ Henry Minute2-Aug-09 9:26 Henry Minute 2-Aug-09 9:26  Please deposit $15,000 in my account and I'll get started. Oh, and by the way I can only do it in my spare time. Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” RGB to Hsv ? Mohammad Dayyan17-Jul-09 20:50 Mohammad Dayyan 17-Jul-09 20:50  Hi. How can we convert a RGB code to its equivalent in Hsv ? Thanks. Re: RGB to Hsv ? Luc Pattyn18-Jul-09 0:03 Luc Pattyn 18-Jul-09 0:03  by using some code, that can be found in a CP article; search for RGB HSV Luc Pattyn [Forum Guidelines] [My Articles] The quality and detail of your question reflects on the effectiveness of the help you are likely to get. Show formatted code inside PRE tags, and give clear symptoms when describing a problem. Re: RGB to Hsv ? Tim Craig18-Jul-09 21:13 Tim Craig 18-Jul-09 21:13  Or by doing a simple web search? That's how I found out how to do it. You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists. How to print GDI BarChart? RanaSohail16-Jul-09 18:40 RanaSohail 16-Jul-09 18:40  Hello! I have implemented a barchart on the surface of Windows-Form. how to print it into hard copy. regard, Sohail Re: How to print GDI BarChart? Henry Minute2-Aug-09 9:33 Henry Minute 2-Aug-09 9:33  Assuming that you are using .NET, and you don't say!!! All Control descendants have a DrawToBitmap method. Use that, then all you have to do is work out how to print a Bitmap. Seriously, there are thousands of examples of how to do this, both here on CP and on t'web. Do a little Binging! Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Re: How to print GDI BarChart? RanaSohail5-Aug-09 3:51 RanaSohail 5-Aug-09 3:51  Hi! i m using .Net and have drawn a chart on windows form's client rectangle. i wanna print it. Thanks alot sir Henry. Re: How to print GDI BarChart? Henry Minute5-Aug-09 4:34 Henry Minute 5-Aug-09 4:34  Then I suggest that you do as I said in the my last post. Look up the documentation for Form.DrawToBitmap, read it and experiment. After that try Googling, or Binging for c# print bitmap You might also want to consider filling your Forms client area with a Panel and drawing your bar chart on that, then use Panel.DrawToBitmap instead of the Form version. Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Re: How to print GDI BarChart? RanaSohail6-Sep-09 21:47 RanaSohail 6-Sep-09 21:47  Thank You very much sir...! Great OpenGL 3.1 tutorial Gvizbi10-Jul-09 9:36 Gvizbi 10-Jul-09 9:36  I found this OpenGL 3.1 tutorial on Wikiscripts, this is the first part, but author promised that soon there will be a sequel: Re: Great OpenGL 3.1 tutorial Gvizbi15-Jul-09 8:43 Gvizbi 15-Jul-09 8:43  Source is now available to download! How to move selected objects in OPENGL gourishsio6-Jul-09 19:15 gourishsio 6-Jul-09 19:15  Hi, I am trying to develop a CAD like application using OpenGL and wxWidgets... I have reached at a stage where i can draw a circle, square, load an image, polygon etc.. am also able to zoom and pan.. as a further step, i want to move object, scale it and rotate.. to do this i have written a code to select and pick object that lies under mouse pointer.. Now what do i have to do to move the picked object..?? I tried by finding the difference of old and new points and recalculating the points of the object.. C.x += dx; C.y += dy; where dx and dy are differences of old and new x, and y values resp.. And C.x C.y are original x and y coordinates This is showing some movement. but not as desired.. it isnt moving along with the mouse movement.. For a small mouse movement, it shows a huge displacement and also very fast... so what can be done to make a selected object move along wiith the mouse pointer...?? Also i'm not able to zoom with reference to the mouse pointer.. it zooms with reference to the origin (0,0,0) only.. please help me.. Thanks in advance.. Can I push a per-pixel off-screen bitmap operation onto the Graphics Accelerator (DirectDraw, etc.)? roscler4-Jul-09 20:04 roscler 4-Jul-09 20:04  I have a program running on Windows 2000 or better PC's that needs to do a per-pixel operation on a Windows bitmap. Currently I'm using a tight loop that does little more than a pointer increment followed by a quick add operation on each pixel over the entire bitmap. This is done in real-time so I need it fast. On a 320 x 240 image that ends up being 230,400 addition operations since they are RGB bitmaps (320 x 240 x 3). This is being done in real time on an image stream that is pumping out 25 frames per second. At that resolution it's fast enough, but at 640 x 480 I have to start dropping frames significantly to keep up. I am not displaying the modified bitmap to the screen at any time. Instead I am shipping it off to a remote location over the Internet for display at the destination system. I was wondering if I could push this operation to the Graphics Accelerator using one of Windows Graphics API's like DirectDraw, etc.? Or do PC Graphic accelerators only help with operations that are drawn to the screen (local PC video memory)? I assume that if it's possible I'd need to pump the bitmap to the Graphics Accelerator and then know how to do a global operation on each pixel and then copy it back to local RAM? If it is possible to use the Graphics Accelerator to help with per-pixel operations on a off-screen bitmap, what are the pros and cons? Finally, is there a way to push JPEG decompression and compression operations onto the Graphics Accelerator? If it is possible to do these things I would like to know where a quick easy to dive into sample is. I don't have any need for shading or rotations or any complex graphics operations at all like that. Therefore I would like to avoid wading through a ton of reading just to learn how to do a simple global pixel operation task. Thanks in advance. Re: Can I push a per-pixel off-screen bitmap operation onto the Graphics Accelerator (DirectDraw, etc.)? Baltoro5-Jul-09 10:55 Baltoro 5-Jul-09 10:55  It is well known that calling GetPixel and SetPixel on a bitmap by addressing each pixel separately is an extremely time consuming graphics operation. I recently ran into this thread, (at the MASM32 forum) that tests a number of typical graphics operations and determines the required clock cycles: Graphics, Memory DIB[^]. Skip the assembly code and just check out the listings of clock cycles for the GDI operation,...I think you'll be amazed. The DirectX SDK comes with a utility that displays the capabilities of your graphics accelerator. Basically, what you want is: GetDeviceCaps[^]. And, if your graphics accelerator supports Pixel Shaders, perhaps that would be faster. But, this is very time-consuming and error-prone. BitBlt is much faster,...but, I think what you want is to have the bitmap already altered before you need to display it. Undoubtedly, that occurred to you. I'm assuming that you cannot access the bitmap before your application loads, or starts processing. Re: Can I push a per-pixel off-screen bitmap operation onto the Graphics Accelerator (DirectDraw, etc.)? roscler5-Jul-09 14:50 roscler 5-Jul-09 14:50  Hello Baltoro, I am not using GetPixel/SetPixel. Instead I am using the Bitmap's scanline property to get a pointer to that memory area and simply walking a pointer over that area in a tight loop. I do have access to the bitmap, in fact I call Delphi's JPEG code to decompress, with some optimizations I added to avoid needless memory reallocations between JPEG frames. I have since learned that there is an extension called DXVA (DirectX Video Acceleration), but that it is really tough to work with. However, I was also told that there probably already are JPEG compressors on my system that make use of DXVA. It might end up being an issue of learning how (if possible) to use DirectX to utilize those hardware accelerated compressors, but I have no idea to go about doing that currently. Thanks, Robert Two Cameras Mosaic Algorithm Bob Yiu3-Jul-09 3:34 Bob Yiu 3-Jul-09 3:34  Hi,all. Currently I’ve been developing a Mosaic system of Two Calibrated Cameras using VS2008 and OpenCV , but my algrithm works badly Here is my program routine, Any advice or help would be greatly appreciated! 1. I calibrated two cameras watching a same area, and undistort the input images, 2. then I use cvFindChessBoardCornerGuesses and cvFindCornerSubPix to get corresponding points of two undistorted input images, 3. and I process the corresponding points using cvFindHomography to get the homography of the two cameras 4. finally use cvWarpPerspective to warp the right camera image plane to the left camera image plane But the warped image is extremely different from the ideal one What's wrong with it? Best Wishes! Re: Two Cameras Mosaic Algorithm Tim Craig4-Jul-09 8:41 Tim Craig 4-Jul-09 8:41  How far apart are your cameras? And when you say that when the right image is warped to the left image plane is far from "ideal", do you know what the ideal image should be from theory or what you just expect it should be? Have you tried the OpenCV group on Yahoo Groups? You might be more likely to get a good answer there than here. You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists. I'm a proud denizen of the Real Soapbox[^] ACCEPT NO SUBSTITUTES!!! Re: Two Cameras Mosaic Algorithm Bob Yiu4-Jul-09 22:58 Bob Yiu 4-Jul-09 22:58  Hey,Tim,Thanks for your reply, My right camera is only 15 degree right rotation from the left camera. I know the ideal warp result I've post a message on OpenCV group, http://tech.groups.yahoo.com/group/OpenCV/message/64370 welcome to join discussion Do you know how to get the homography of two cameras by the camera matrix or extrinsic matrix? Thanks! Re: Two Cameras Mosaic Algorithm Tim Craig5-Jul-09 21:12 Tim Craig 5-Jul-09 21:12  Do you have the book "Learning OpenCV"[^]? I noticed a section of homography in it. In my exploration of OpenCV I haven't gotten quite that far. I've been spending a lot of time getting a framework in place so I can quickly and easily write test applications. That and fighting the lack of documentation and weirdness in OpenCV. You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists. I'm a proud denizen of the Real Soapbox[^] ACCEPT NO SUBSTITUTES!!! Re: Two Cameras Mosaic Algorithm Bob Yiu6-Jul-09 23:43 Bob Yiu 6-Jul-09 23:43  I've got the book "learning Opencv",but it doesn't solved my problem So how is it going of your framework? Re: Two Cameras Mosaic Algorithm Tim Craig7-Jul-09 17:59 Tim Craig 7-Jul-09 17:59  The one thing I got out of the homography section was that he suggests using at least 10 images when using the chessboard technique to get a good matrix. That's more than I expected. My framework has been one step forward then two steps back. I had to get a new computer last year and to get it quickly, I took one with Vista preinstalled. OpenCV and Vista don't get along well. I've finally started gaining traction. After a false start, I settled on wxWidgets for the GUI and have a lot of the basics of OpenCV wrapped in C++ to hide some of the ugliness (like the relationship between CvMatrix and IplImage ). Right now I'm working through object detection and obstacle avoidance for mobile robots. You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists.

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