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I think it would be easier to scan top-down horizontally until you find a non-white pixel. That
gives you the top. Then scan left-right vertically until you find a non-white pixel. That gives
you the left.
I think the code you've shown is just to get the top - maybe - unless there's colored pixels
higher on the right half of the image 
Also, did you mean to put these arguments in this order? GetPixel(j,i);
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Simple bug... Unless I'm reading this wrong, that "break" in the else block is going to knock you right out of the "i" loop, but not out of the surrounding "j" loop. Hence it'll find the first non-white pixel, then continue on the next row.
Also, as another reply mentioned, check your i/j for row/column. I suggest using variable names like "row" and "col" to avoid confusion, because it looks like "j" is counting rows, but being placed in "width_left", and vice versa.
Oh, and if you want a more efficient algorithm, you might want to check pixels in a different order... What you're doing now is, using numbers to represent outer loop steps:
11111111
22222222
33333333
etc.
I think what you really want to do is:
12345
22345
33345
44445
55555
etc.
Little more complicated, but might work better.
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Hi everyone...
I have a concrete problem but I will firstly introduce it in an abstract:
An algorithm scans a 24-bit bitmap data, an array of bytes. When the loop encounters a white pixel it adds the Point to the array of Points.
After the loop had scanned the entire bitmap I use the array of points to create the GraphicsPath
I draw the path and I get exactly what I want.
The problem is when checking for a hit test!
I use the myPath.IsVisible(point.X, point.Y) and here is where the problem occurs!
I have analyzed the array of points contained within the path object and have noticed that the myPath.IsVisible(point.X, point.Y) only return true in ONE SPECIAL CASE!
When the loop scans the first line of the bitmap and runs into a white pixel it will add that point to the array.
So this very point, the first white one in the first bitmap line, is the crucial one!
How? Well it seems that every point having its X coordinate greater than the very first point's X coordinate gets accounted form when calling myPath.IsVisible(point.X, point.Y). This means that every point in the path's array of points whose X coordinate is lesser than the first co ordinate's X will not be accounted for the hit test!
This manifests in way that, if operating with an irregular elliptic resembling shape, only the right side is accounted for the hit test, not the left one!
I am more that happy to post the project for viewing and examining, it 100+ lines of code, but if someone has a solution to this I would be more than happy to hear it.
By the way, I have a good experience with wi32 HRGN structures, they did not give me such problems!
Thanks to everyone in advance!
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This doesn't help you any, but I was involved in, tested, and comfirmed a bug in the GDI+
hittesting with regions. I still have the code that shows the flaw. It involved using a union
of two rect regions and hit testing in between them.
I wonder if it's related...
Good luck!
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Thanks, It helps me in the way that now I know I was right about the bug and can start searching for an alternative.
Right now I will attempt importing the win32 PtInRegion and utilize it.
If I get a success on this I will post the solution.
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So, here is the famous solution, as I promised...
The case with my code was that I called myPath.AddLines(...) which caused an error!
The fact is that path wad drawing properly, i.e. its drawn shape is what I expected, though the path data was corrupted!
The solution was to create a 1x1 rectangle for each of the points (new Rectangle(points[i].X, points[i].Y, 1, 1)) and then call myPath.AddRectangles(...)
After applying this method both, the drawn image and the hit testing worked just fine!
I hope this helps to someone.
By the way, after spending the entire day I got the solution of iterating through the monochrome (1 bit per pixel) bitmap data and checking if the pixel is black or white!
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There are a lot of image libraries out there that handle converting image bit depths but is there any that solely focus on bit depth conversions?
I need something that can convert from 32bit with alpha to 8bit, 4bit, etc. and vice-versa preferably in C#.
I understand I should probably write these functions myself but it's extremely confusing working with the individual pixels etc. and I know that I could never make it as efficient as something that surely exists out there somewhere. I'm just having a hell of a time finding what I need. Even the image libraries I've found that include functions to convert bit depths convert to grayscale which is not what I need.
Thanks
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hey all...
i've a question in the Photoshop application,
i've a small pic wz resolution 72 pixel/inch ... i wanna increase the resolution so that i can enlarge the pic but everytime i do that the pic gets blured & cant reach a tool 2 help me purify it .. does any1 has an answer 4 that or is it impossible 2 be done ??
thx ...
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right click on the image frame.(i mean the frame at the top of the inserted image,which shows the image 's name.)there is option for image size.change it accordingly and save in appropriate format.
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friendship wrote: i wanna increase the resolution so that i can enlarge the pic
You can't. It will only make the pixels bigger, which is why the picture is blurred. increasing the resolution would either make the picture smaller (to accomodate the higher resolution), or would require more image data if you were to make the picture larger.
Cheers,
Drew.
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Hey frnds
Can any one tell me how to create 8 bit bitmap
thx in advance
Born To Code
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You've asked this before....what part of the process is giving you trouble?
Do you want a device-dependent bitmap, a device-independent bitmap, ...??
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Can u plz explain how to draw 8 bit bitmap using palette.
The bitmap should be of 256 color,
thnaks
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I still don't know what type of bitmap you're using.
You draw 8-bit bitmaps the same as any bitmaps. You can use GetDeviceCaps(RASTERCAPS) to check
if the destination DC is a palette device. If it is, select your palette into it, call
RealizePalette() (usually), and draw the bitmap.
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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thank u Sir,
but tell me how to know whether the destination DC is a palette device or not?
if not then how to set.
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rahul.shendurnikar wrote: how to know whether the destination DC is a palette device or not?
if (GetDeviceCaps(hdc, RASTERCAPS) & RC_PALETTE)
{
}
How to set it depends on the device. For a monitor, it's based on the video mode.
For a printer device it's based on the bitmap format selected into the dc. etc...
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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 hey
my destination DC is not a palette device.
destination DC is my Monitor.
Can u plz send me code snipet which create 8 bit bitmap usning palette.
the palette aaray should be.....
static int ARGB[256][3] =
{
{0,0,0}, //0
{48,0,0}, //1
{48,48,48}, //2
{0,16,16}, //3
{32,32,32}, //4
{16,16,16}, //5
{0,48,0}, //6
{48,48,0}, //7
{0,48,48}, //8
{0,16,16}, //9
{80,80,80}, //10
{96,96,96}, //11
{96,96,96}, //12
{112,112,112}, //13
{128,128,128}, //14
{144,144,144}, //15
{160,160,160}, //16
{160,160,160}, //17
{176,176,176}, //18
{192,192,192}, //19
{208,208,208}, //20
{208,208,208}, //21
{208,208,208}, //22
{224,224,224}, //23
{224,224,224}, //24
{224,224,224}, //25
{240,240,240}, //26
{96,48,48}, //27
{96,48,0}, //28
{96,0,0}, //29
{96,0,96}, //30
{96,48,96}, //31
{160,0,96}, //32
{160,48,96}, //33
{160,0,32}, //34
{160,48,48}, //35
{160,48,0}, //36
{160,0,0}, //37
{160,96,96}, //38
{160,96,48}, //39
{160,96,0}, //40
{208,0,96}, //41
{208,48,96}, //42
{208,96,96}, //43
{208,96,0}, //44
{208,96,48}, //45
{208,48,48}, //46
{208,48,0}, //47
{208,0,0}, //48
{240,96,96}, //49
{240,0,112}, //50
{240,48,96}, //51
{240,0,96}, //52
{240,96,48}, //53
{240,96,0}, //54
{240,16,32}, //55
{240,80,80}, //56
{240,0,0}, //57
{240,128,128}, //58
{240,160,160}, //59
{240,160,160}, //60
{240,160,208}, //61
{240,96,208}, //62
{240,96,240}, //63
{224,16,208}, //64
{224,16,208}, //65
{240,0,176}, //66
{240,0,160}, //67
{240,48,160}, //68
{240,96,160}, //69
{208,0,144}, //70
{208,0,160}, //71
{208,48,160}, //72
{208,96,160}, //73
{240,0,208}, //74
{208,96,208}, //75
{208,0,208}, //76
{208,96,208}, //77
{208,48,208}, //78
{240,0,240}, //79
{240,48,240}, //80
{240,160,240}, //81
{240,208,240}, //82
{208,160,96}, //83
{208,160,48}, //84
{208,160,0}, //85
{208,160,48}, //86
{208,160,160}, //87
{240,208,160}, //88
{240,208,160}, //89
{240,208,192}, //90
{240,208,208}, //91
{208,160,208}, //92
{176,160,144}, //93
{208,208,160}, //94
{208,208,160}, //95
{208,208,160}, //96
{240,240,208}, //97
{240,240,208}, //98
{96,96,0}, //99
{96,96,48}, //100
{0,96,0}, //101
{48,96,0}, //102
{0,96,48}, //103
{48,96,48}, //104
{0,128,0}, //105
{96,160,48}, //106
{96,160,96}, //107
{48,160,96}, //108
{0,160,96}, //109
{0,160,48}, //110
{48,160,48}, //111
{48,160,0}, //112
{0,160,0}, //113
{48,208,0}, //114
{0,208,0}, //115
{96,208,0}, //116
{96,208,96}, //117
{96,208,96}, //118
{0,208,48}, //119
{48,208,48}, //120
{96,208,48}, //121
{0,208,96}, //122
{48,208,96}, //123
{0,240,0}, //124
{96,240,96}, //125
{48,240,48}, //126
{48,240,96}, //127
{0,240,96}, //128
{96,240,48}, //129
{96,240,0}, //130
{160,240,0}, //131
{160,240,48}, //132
{160,240,96}, //133
{192,224,192}, //134
{176,224,192}, //135
{176,224,192}, //136
{208,240,208}, //137
{208,240,0}, //138
{208,240,48}, //139
{208,240,96}, //140
{240,208,96}, //141
{240,208,48}, //142
{240,208,0}, //143
{128,128,0}, //144
{160,160,48}, //145
{160,160,64}, //146
{160,160,96}, //147
{176,192,0}, //148
{208,208,48}, //149
{208,208,96}, //150
{160,208,48}, //151
{160,208,96}, //152
{160,208,96}, //153
{160,208,0}, //154
{160,208,96}, //155
{240,160,96}, //156
{240,160,48}, //157
{240,160,0}, //158
{160,240,160}, //159
{240,240,0}, //160
{240,240,96}, //161
{240,240,48}, //162
{224,224,0}, //163
{160,240,160}, //164
{0,240,160}, //165
{48,240,160}, //166
{96,240,160}, //167
{48,240,160}, //168
{0,240,160}, //169
{48,208,160}, //170
{0,208,160}, //171
{0,208,160}, //172
{48,208,160}, //173
{96,208,160}, //174
{176,176,144}, //175
{48,96,96}, //176
{0,96,96}, //177
{0,128,128}, //178
{0,160,160}, //179
{96,160,160}, //180
{48,240,208}, //181
{0,240,208}, //182
{160,240,208}, //183
{0,208,208}, //184
{48,208,208}, //185
{96,208,208}, //186
{0,192,208}, //187
{160,240,240}, //188
{96,240,240}, //189
{0,240,240}, //190
{48,240,240}, //191
{96,240,240}, //192
{208,240,240}, //193
{208,240,240}, //194
{160,208,240}, //195
{160,208,240}, //196
{208,208,240}, //197
{160,160,208}, //198
{208,0,240}, //199
{208,160,240}, //200
{160,48,208}, //201
{160,0,208}, //202
{160,96,208}, //203
{208,96,240}, //204
{208,48,240}, //205
{176,80,192}, //206
{160,96,160}, //207
{160,0,160}, //208
{160,48,160}, //209
{128,0,128}, //210
{160,48,240}, //211
{160,0,240}, //212
{160,96,240}, //213
{96,0,160}, //214
{96,48,160}, //215
{48,0,96}, //216
{0,0,96}, //217
{0,48,96}, //218
{48,48,96}, //219
{0,0,112}, //220
{0,0,112}, //221
{0,0,128}, //222
{160,160,240}, //223
{48,48,160}, //224
{0,0,160}, //225
{0,48,160}, //226
{48,0,160}, //227
{48,96,160}, //228
{96,96,160}, //229
{0,96,208}, //230
{48,96,208}, //231
{0,0,208}, //232
{96,48,208}, //233
{48,48,208}, //234
{0,48,208}, //235
{0,0,240}, //236
{96,0,240}, //237
{96,96,240}, //238
{0,96,240}, //239
{96,48,240}, //240
{48,48,240}, //241
{48,96,240}, //242
{96,96,208}, //243
{96,160,240}, //244
{48,160,240}, //245
{0,160,240}, //246
{96,160,224}, //247
{96,160,224}, //248
{0,160,208}, //249
{96,160,208}, //250
{48,160,208}, //251
{0,192,224}, //252
{0,208,240}, //253
{48,208,240}, //254
{96,208,240} //255
};
thanks in advance..
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LONG lImageWidth = 320;
LONG lImageHeight = 240;
WORD wBitsPerPixel = 8;
LONG lBytesPerRow = (((lImageWidth * (long)wBitsPerPixel + 31L) & (~31L)) / 8L);
BITMAPINFO *pbmi = (BITMAPINFO *)new BYTE[sizeof(BITMAPINFO) + sizeof(RGBQUAD) * 255];
memset(pbmi, 0, sizeof(BITMAPINFO));
pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
pbmi->bmiHeader.biWidth = lImageWidth;
pbmi->bmiHeader.biHeight = lImageHeight;
pbmi->bmiHeader.biPlanes = 1;
pbmi->bmiHeader.biBitCount = wBitsPerPixel;
pbmi->bmiHeader.biCompression = BI_RGB;
pbmi->bmiHeader.biSizeImage = lBytesPerRow * lImageHeight;
for (int i = 0; i < 256; i++)
{
pbmi->bmiColors[i].rgbBlue = (BYTE)ARGB[i][2];
pbmi->bmiColors[i].rgbGreen = (BYTE)ARGB[i][1];
pbmi->bmiColors[i].rgbRed = (BYTE)ARGB[i][0];
pbmi->bmiColors[i].rgbReserved = 0;
}
BYTE* pBitmapBits;
HDC hdc = ::GetDC(0);
HBITMAP hBitmap = ::CreateDIBSection(hdc, pbmi, DIB_RGB_COLORS, &pBitmapBits, NULL, 0);
::ReleaseDC(0, hdc);
if (hBitmap)
{
memset(pBitmapBits, 0, pbmi->bmiHeader.biSizeImage);
...
...
::DeleteObject(hBitmap);
delete[] (BYTE *)pbmi;
}
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Thank u so much...
Born To Code
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Hi All,
I am facing quite starnce problem.I am Capturing Audio Stream from TV Tuner Card and Play Back using DirectShow.First Time its work fine.But When i stop the filter graph or exit the application and again tried to restart it.The Audio is not captured.But After resttating my machine (PC) it again work fine.
Please let me know where i am wromg.
Thaks in Advance.
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hey everybody...
I hope someone can help me caus I'm trying to implement this cube mapping thing for two days now...
I've been to all those websites...
There must be some small mistake in my code and I just can't find it...
<br />
...<br />
(InitGL)<br />
CubeMappingAvailable = CheckOpenGLExtension("GL_ARB_texture_cube_map");<br />
<br />
myTextureLoader.LoadCubeMap("right.jpg",<br />
"left.jpg",<br />
"bottom.jpg",<br />
"top.jpg",<br />
"front.jpg",<br />
"back.jpg",<br />
&myCubeMap);<br />
<br />
<br />
glGenTextures(1, &dest->TextureID);<br />
glBindTexture(GL_TEXTURE_CUBE_MAP_ARB, dest->TextureID);<br />
<br />
glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);<br />
glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);<br />
<br />
LoadFromFile(fileRight, &dest->right, 1);
LoadFromFile(fileLeft, &dest->left, 2);<br />
LoadFromFile(fileTop, &dest->top, 3);<br />
LoadFromFile(fileBottom, &dest->bottom, 4);<br />
LoadFromFile(fileFront, &dest->front, 5);<br />
LoadFromFile(fileBack, &dest->back, 6);<br />
<br />
<br />
(...)<br />
glTexParameterf(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);<br />
glTexParameterf(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR);<br />
<br />
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB+(cube-1),<br />
0,<br />
components,<br />
pTexture->Width,<br />
pTexture->Height,<br />
0,<br />
pTexture->Type,<br />
GL_UNSIGNED_BYTE,<br />
pImgData);<br />
<br />
glDisable(GL_TEXTURE_2D);<br />
glEnable(GL_TEXTURE_CUBE_MAP_ARB);<br />
glEnable(GL_TEXTURE_GEN_S);<br />
glEnable(GL_TEXTURE_GEN_T);<br />
glEnable(GL_TEXTURE_GEN_R);<br />
glBindTexture(GL_TEXTURE_CUBE_MAP_ARB, desCube->TextureID);<br />
<br />
<br />
glDisable(GL_TEXTURE_GEN_S);<br />
glDisable(GL_TEXTURE_GEN_T);<br />
glDisable(GL_TEXTURE_GEN_R);<br />
glDisable(GL_TEXTURE_CUBE_MAP_ARB);<br />
Sorry for not posting more... but I think It's more a general mistake and I put everything in different classes and methods, so posting more might make everything more complicated...
thanx in advance
zqueezy
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damn, I found it finally...
I had to add:
<br />
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_EXT);<br />
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_EXT);<br />
glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_EXT);<br />
after glTexImage2D
I cannot see really why, and many tuts left that out...
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i want to work on PABX Exchange but i dont have any idea about this, is there any built in API or Serial Classes in VB.NET can any one tell me about this how should i work on it
syed imran azmat
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So, what does this have to do with Graphics? You may want to Google for "PABX VB.NET" for examples and discussions.
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Hey Friends,
I want to Convert 32 bit Bitmap tp 8 bit bitmap.
Here i have to used palette.
CAn any body tell me abt this conversion and about palete.
Thanks in advance.
Born To Code
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