Graphics

PNG Alpha blending/channel in VC++ 6.0?

12-Sep-07 7:01

ptr_Electron wrote:
suggestion are greatly appericated

google [correlation tracking algorithm]

_________________________
Asu no koto o ieba, tenjo de nezumi ga warau.
Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)

StarMeteor10-Sep-07 21:00

StarMeteor

10-Sep-07 21:00

Hi All,

I am writing an application which try to show PNG file as a dialog background using GDI+
I have successfully using the PNG as background (using Graphics::DrawImage()), however, I found that the loaded PNG seems not apply the alpha channel information. What I should do?

Thanks! Big Grin | :-D

Vincent

Most common used color in an image?

mm-2k10-Sep-07 7:11

10-Sep-07 7:11

Hi,

Is there any way to get the most common used color of an image (jpg) in C#/VB? I have been searching the for "image histogram" and "image quantization", because it seams like these are the most common terms. No luck yet.

I would like something to categorize images by color.

Best regards

Carsten Petersen
Denmark

Russell^'10-Sep-07 8:06

Russell^'

10-Sep-07 8:06

mm-2k wrote:
I have been searching the for "image histogram" and "image quantization", because it seams like these are the most common terms. No luck yet.

Why? It seams really the best way ... Big Grin | :-D

You will have probally only to perform the algorithms setting thresholds..not more Unsure | :~

Russell

mm-2k10-Sep-07 8:09

10-Sep-07 8:09

Hi Russel,

Thanks for the reply.

I am searching for an example or description on how to do it, but haven't had any luck yet.

Russell^'10-Sep-07 8:44

Russell^'

10-Sep-07 8:44

a simple example for "Histogram":
* convert the image in RGB (same if HSV)
* find min and max value for R ,G ,B in all the image
* quantize (for example using 50 slices per color) the range of values in that min-max interval (for every 3 colors, so you will fix 50x50x50 cubes/volumes)
* then look to the pixel of the image and count how many time a color fall in a cube
* when finished the cube with the greater number of pixel inside is the color that you are seraching

*eleway you can analise separately R, G and B. In this way you will have 50+50+50 linear intervals, not volumes.
Smile | :)

Russell

Luc Pattyn10-Sep-07 10:11

Luc Pattyn

10-Sep-07 10:11

Can you expand on the higher purpose of this? and on the kind of pictures?

From your requirements/intentions you probably first will have to decide which is the
right color space to use (RGB, HSL, just hue, ...), then the required accuracy.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google

mm-2k10-Sep-07 10:17

10-Sep-07 10:17

Hi Luc,

Thanks for the reply.

I want to use this, to categorize images (web images - only JPG/RGB) by it's color. This will be used on a e-commerce site. When a user uploads a image in the backend, i want to extract the most common used color of the current image (eg. 5-10 colors per image). These values will be stores in the database, with a reference to the image. This will allow me to make a categorizing of the images in the frontend.

If you look at this page (http://goincase.com/products/), on the right corner, you can "Browse all by color". This is what i want to achieve - automatically when images is uploaded.

Best regards

Carsten Petersen

Luc Pattyn10-Sep-07 10:52

Luc Pattyn

10-Sep-07 10:52

Hi Carsten,

I have two comments:

1.
the number of colors in the categorization is very limited and they color collection seems
to be predefined. If so, one only needs to determine in which category a picture would fit
best. One way of doing this is by calculating some "error function" for each of the
categories (say the sum over all pixels of the squared deviation between actual pixel
and category color). The main problem remaining is to determine the relevant pixels:
one has to exclude the background, and all zones that are not part of the selectable color
(display, keyboard, whatever).

2.
I am not convinced at all they did it in an automatic way; seems to me if Ipod sleeve
so and so comes in "green" and "blue" according to the manufacturer, they make sure to
have two pictures and add them to the "green" and "blue" category respectively.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

mm-2k10-Sep-07 19:21

10-Sep-07 19:21

True, i want to show these colors when the image is uploaded. The user can then select one of the colors, or define one manually. This is only for guidance.

El Corazon11-Sep-07 3:36

11-Sep-07 3:36

mm-2k wrote:
Is there any way to get the most common used color of an image (jpg) in C#/VB? I have been searching the for "image histogram" and "image quantization", because it seams like these are the most common terms. No luck yet.

I am surprised, image histograms are very common. However, if you are looking for tri-color histograms as apposed to single channel (red only, blue only, etc.), that is why. You will find that in most natural images (not created artificially on a computer, or touched up), that most true color (RGB) references will have a very low count. Why? Well, to be frank, it is because in 24bit color (RGB, 8 bits each), any given single color reference is 1:16,777,216 and a given image such as 1024x768 is only 786,432 pixels. Even going up to a relatively large image size, 2921 x 2184 which is a 6megapixel image, the odds of having any given color combination more than once is very low. So doing a color histogram on the complete 24bit color value will generally produce a histogram count of 1 or 0 for all colors with the occasional exception.

If you have seen the posters that use images as tiles to reconstruct another much larger image, these are done by classifying the over-all hue of the image. A histogram and color analysis is easy on a single channel, since it is just a series of 256 values. Over a six megapixel image or even something as small as a 1024x768 image, the number of counts of any single value are easily histogrammed and classified.

Plus as mentioned above by others, you can change color-space to get other channel references. Common channel references are RGB CMYK and YUV. You simply convert color space to the appropriate system, then examine your histogram on any given channel. You can even do all three color spaces and histogram each channel to see which classifies your image best.

_________________________
Asu no koto o ieba, tenjo de nezumi ga warau.
Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)

image processing toolkits | batch image processing

C^hris L^osinger26-Sep-07 5:19

C^hris L^osinger

26-Sep-07 5:19

1. allocate an array of 256x256x256 integers. set them all to 0.

2. for every RGB pixel in the image, increase ar[r * 256 * 256 + g * 256 + b] by one.

3. find the element in the array with the highest value.

old unix gl mook mosies over to VS 8 beta 2

dr d b karron6-Sep-07 11:32

dr d b karron

6-Sep-07 11:32

confound it; how do i just make my opengl windows and track the mouse state ?

I'm compileing sample opengl code ok in visual studio, but now i'm getting linkage errors. Searching (find|grep for those who used to know) through my little iddy biddy laptop turns up no .lib or .dll (libogl* or gl*.dll).

What is the relationship between runnin openGL and .net 1.1, .net 2, .net 3 and .net 3.5. What is .net anyway ? It seems that the old demos like older .net.

But i'm trying to understand what is going on. I want to bring forward my old c++ code and rewrite it for the brave new world (kids these days!).

I'm remotely controlable for someone to take the time to skype in and unyte to my keyboard and show me the errors of my old fashioned ways.

I'm looking forward to using a modern c++ compiler and making all sorts of math types (with and without STL).

My other problem is getting lots and lots of shared memory. I will move up to a 64 bit big pointer system soon. First I need to get my toes wet with VS 8 and this funny new world.

Cheers!

dr. K

-----------
libcmtd.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glFlush@0 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glCallList@4 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glColor3dv@4 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glRotated@32 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glTranslated@24 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glLoadIdentity@0 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glMatrixMode@4 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glColorMaterial@8 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glClear@4 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glClearColor@16 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glEnable@4 referenced in function "public: void __thiscall CGLEasyView::DrawScene(void)" (?DrawScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glEndList@0 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glEnd@0 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glVertex3d@24 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glNormal3d@24 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glBegin@4 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glNewList@8 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__wglMakeCurrent@8 referenced in function "public: void __thiscall CGLEasyView::PrepareScene(void)" (?PrepareScene@CGLEasyView@@QAEXXZ)
gleasvw.obj : error LNK2019: unresolved external symbol _gluErrorString@4 referenced in function "public: void __thiscall CGLEasyView::OutputGlError(char *)" (?OutputGlError@CGLEasyView@@QAEXPAD@Z)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glGetError@0 referenced in function "public: void __thiscall CGLEasyView::OutputGlError(char *)" (?OutputGlError@CGLEasyView@@QAEXPAD@Z)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__wglCreateContext@4 referenced in function "protected: int __thiscall CGLEasyView::OnCreate(struct tagCREATESTRUCTW *)" (?OnCreate@CGLEasyView@@IAEHPAUtagCREATESTRUCTW@@@Z)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__glViewport@16 referenced in function "protected: void __thiscall CGLEasyView::OnSize(unsigned int,int,int)" (?OnSize@CGLEasyView@@IAEXIHH@Z)
gleasvw.obj : error LNK2019: unresolved external symbol _gluPerspective@32 referenced in function "protected: void __thiscall CGLEasyView::OnSize(unsigned int,int,int)" (?OnSize@CGLEasyView@@IAEXIHH@Z)
gleasvw.obj : error LNK2019: unresolved external symbol __imp__wglDeleteContext@4 referenced in function "protected: void __thiscall CGLEasyView::OnDestroy(void)" (?OnDestroy@CGLEasyView@@IAEXXZ)
C:\Documents and Settings\karron\My Documents\Visual Studio 2008\Projects\helo2\Debug\gleasy.exe : fatal error LNK1120: 25 unresolved externals

dr d b karron

Re: old unix gl mook mosies over to VS 8 beta 2

El Corazon8-Sep-07 5:19

Imange Manipluation with Asp.Net

8-Sep-07 5:19

do you have the platform SDK installed? Any of this[^] help?

_________________________
Asu no koto o ieba, tenjo de nezumi ga warau.
Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)

Mustakim Mansuri5-Sep-07 19:43

Mustakim Mansuri

5-Sep-07 19:43

Hi

I need to impliment functionality for online image editing that support add text to image, rotate image, ovaerlap new image to existing image, zooming image, crope.

Please give me refferance of such website that can provide tool for image editor.

I want same functionality as in http://www.buildasign.com/PowerDesign.aspx?T=4476553256504A7644356F3D

I am finding tool or source in GDI+ that support this functionality.

If you know any component, free or paid please give me refferance.

Please help me.
Thanks in advance

Mustakim Mansuri

TextureLoader - InvalidOperationException

Katerinochka4-Sep-07 5:52

Katerinochka

4-Sep-07 5:52

Hi,

I am trying to do some graphics with Direct3D for Windows Mobile.

Everything works fine until I create a texture:

texture = TextureLoader.FromFile(dev, "My Documents\\abc.bmp", 200, 200, 0, Usage.None, Format.A8R8G8B8,Pool.Managed,

Filter.None, Filter.None, 0);

This throws the InvalidOperationException with no further details how to solve it.

The alternative ways to create a texture lead to the same exception:

texture = TextureLoader.FromStream(dev,

System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream("Project1.abc.bmp"));

texture = TextureLoader.FromFile(dev,"Project1.abc.bmp");

Could someone help me with this please?
I would very appreciate any advice!!!

Thank you,
Katerina

display driver

amit.code3-Sep-07 22:46

amit.code

3-Sep-07 22:46

Can any tell me how to start programming or reading of display drivers (xp or vista )any link or any tutorial or any forum where i can get help. i dont have any basic knowledge of drivers too.

thanx

prashant jain malviya national institute of technology

Re: display driver

Christian Graus4-Sep-07 4:23

Christian Graus

4-Sep-07 4:23

What exactly are you trying to do ?

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Graphics for Unix in C++

MartyExodus3-Sep-07 11:54

MartyExodus

3-Sep-07 11:54

Hello, I'm not exactly certain that this is the riht place to post this. If I am wrong, could someone please redirect me?ve never done graphics programming,

Anyhow, here's my question. What can I use to print graphics to the screen in Unix with C++? I'm rather restricted on platform and compiler choice, but other than that I'm free to do what I want. I'm telnet-ing into a unix server, so I don't know if that will affect my ability to download libraries like OpenGL.

I've never done graphics programming so everything here is somewhat new to me. If I can gain to draw and move bitmaps on the screen it will be enough.

Thanks to anyone who helps or at least pushes me in the right direction.

Re: Graphics for Unix in C++

El Corazon4-Sep-07 4:02