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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transistional//EN"><html><head><title>OpenLayer Offline Manual</title><style type="text/css" media="all">@import "../CrystalStyle.css";</style><body bgcolor="FFFFFF" ><div align="center" style="pagestyle"><table width="60%"><tr><td><div class="parentLinks"><a href="../index.html">OpenLayer</a> | <a href="../Bitmap.html">Bitmap</a> | <a href="../Bitmap/GetPixel.html">GetPixel</a></div><br><div class="BigHeader">GetPixel</div><br><div class=""><div class="Surrounded"><table><tr valign="top"><td align="right"><div class="FuncDef"><strong><font color="#777733">inline</font> <a href="../Rgba.html"><font color="#0000CC">Rgba</font></a> <a href="../Bitmap/GetPixel.html"><font color="#0000CC">GetPixel</font></a>(</strong></div></td><td><div class="FuncDef"><strong><font color="#777733">int</font> x, <font color="#777733">int</font> y ) <font color="#777733">const</font>;
<br></strong></div></td></tr></table>
<br>Returns the color value of the specified pixel as an Rgba color.
<br></div>
<br>No checking is done wether the pixel actually lies inside the pixel so make sure that you don't try to read a pixel out of the bounds of the bitmap, which would lead to a crash.
<br>
<br>This function is <b>relatively slow</b> so it's best to not to call this function per each pixel in the Bitmap! If you read only a few dozen of pixels per frame it shouldn't be too slow, though.
<br>
<br>To read the whole Bitmap, you should first get a copy of it in the memory by calling <a href="../Canvas/GetMemoryBitmap.html"><font color="#0000CC">GetMemoryBitmap</font></a> instead.
<br>
<br>Since OpenLayer 2.0, this function reads the color from the texture information in the graphics card. Thus if the Bitmap isn't loaded in the graphics card, this function won't work!</div><br><div class="MediumHeader">Examples</div><br><div class="Code"><a href="../Bitmap.html"><font color="#0000CC">Bitmap</font></a> myBmp( ... );
<br>
<br><font color="#999922">// Get the color of the pixel x = 7, y = 5 in the bitmap //</font>
<br><a href="../Rgba.html"><font color="#0000CC">Rgba</font></a> color = myBmp.<a href="../Bitmap/GetPixel.html"><font color="#0000CC">GetPixel</font></a>( <font color="#994400">7</font>, <font color="#994400">5</font> );
<br>
<br><font color="#999922">// That would lead to a crash if the size of the bitmap would be less than 8x6 //</font>
<br><font color="#999922">// The safe way would be: //</font>
<br>
<br><a href="../Rgba.html"><font color="#0000CC">Rgba</font></a> color;
<br><font color="#777733">int</font> x = <font color="#994400">7</font>, y = <font color="#994400">8</font>;
<br>
<br><font color="#447711">if</font>( x >= <font color="#994400">0</font> && x < myBmp.<a href="../Canvas/Width.html"><font color="#0000CC">Width</font></a>() &&
<br> y >= <font color="#994400">0</font> && y < myBmp.<a href="../TextRenderer/Height.html"><font color="#0000CC">Height</font></a>() ) {
<br>
<br> color = myBmp.<a href="../Bitmap/GetPixel.html"><font color="#0000CC">GetPixel</font></a>( <font color="#994400">7</font>, <font color="#994400">5</font> );
<br>}</div><div class=""><br><br><div class="MediumHeader">Other functions of the class <a href="../Bitmap.html"><font color="#0000CC">Bitmap</font></a></div><div class="Surrounded"><table size="100%" cellpadding="0" cellspacing="0"><tr><td halign="center" class="funclist"><a href="../Bitmap/Load.html">Load</a></td><td width="65%" halign="center"><div class="smalltext">Loads the bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Blit.html">Blit</a></td><td width="65%" halign="center"><div class="smalltext">Draws the Bitmap to the screen</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/BlitRotated.html">BlitRotated</a></td><td width="65%" halign="center"><div class="smalltext">Draws the Bitmap to the screen rotated along a point</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/BlitStretched.html">BlitStretched</a></td><td width="65%" halign="center"><div class="smalltext">Draws the Bitmap to the screen stretched to the specified size</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/BlitTransformed.html">BlitTransformed</a></td><td width="65%" halign="center"><div class="smalltext">Draws the Bitmap to the screen rotated and stretched</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/BlitDistorted.html">BlitDistorted</a></td><td width="65%" halign="center"><div class="smalltext">Draws the Bitmap to the screen with the given corner points</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Width.html">Width</a></td><td width="65%" halign="center"><div class="smalltext">Returns the width of the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Height.html">Height</a></td><td width="65%" halign="center"><div class="smalltext">Returns the height of the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/LoadListOfBitmaps.html">LoadListOfBitmaps</a></td><td width="65%" halign="center"><div class="smalltext">Loads a list of bitmaps from the disk</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/GetPixel.html">GetPixel</a></td><td width="65%" halign="center"><div class="smalltext">Returns the color value of a pixel</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Destroy.html">Destroy</a></td><td width="65%" halign="center"><div class="smalltext">Destroys the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/IsValid.html">IsValid</a></td><td width="65%" halign="center"><div class="smalltext">Checks if the Bitmap was loaded correctly</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Save.html">Save</a></td><td width="65%" halign="center"><div class="smalltext">Saves the Bitmap to disk with the specified filename</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/CopyFromScreen.html">CopyFromScreen</a></td><td width="65%" halign="center"><div class="smalltext">Copies a region of the game window to the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/GetMemoryBitmap.html">GetMemoryBitmap</a></td><td width="65%" halign="center"><div class="smalltext">Returns a memory bitmap copy of (part of) the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/GetCollisionPoly.html">GetCollisionPoly</a></td><td width="65%" halign="center"><div class="smalltext">Returns the generated collision polygon for the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/SetDefaultPivot.html">SetDefaultPivot</a></td><td width="65%" halign="center"><div class="smalltext">Sets the default pivot point</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/GetDefaultPivot.html">GetDefaultPivot</a></td><td width="65%" halign="center"><div class="smalltext">Returns the default pivot point</div></td></tr><tr><td colspan="2"><br><div class="SmallHeader"><font color="#775500">Advanced functions</font></div><br></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/GetPixelPacked.html">GetPixelPacked</a></td><td width="65%" halign="center"><div class="smalltext">
Returns the color value of the specified pixel in a packed integer</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/SendToGPU.html">SendToGPU</a></td><td width="65%" halign="center"><div class="smalltext">Sends the Bitmap to the graphics card</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/UnloadFromGPU.html">UnloadFromGPU</a></td><td width="65%" halign="center"><div class="smalltext">Unloads the Bitmap from the graphics card</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/Select.html">Select</a></td><td width="65%" halign="center"><div class="smalltext">
Selects the Bitmap as the active texture of OpenGL</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/UseAutoDelete.html">UseAutoDelete</a></td><td width="65%" halign="center"><div class="smalltext">
Chooses the Bitmap to be automatically deleted when the program quits</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/HasAlphaChannel.html">HasAlphaChannel</a></td><td width="65%" halign="center"><div class="smalltext">Checks if the Bitmap has an alpha channel</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/StartFastBlitting.html">StartFastBlitting</a></td><td width="65%" halign="center"><div class="smalltext">This function should be called right before using FastBlit</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/FastBlit.html">FastBlit</a></td><td width="65%" halign="center"><div class="smalltext">A faster version of Blit</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/FinishFastBlitting.html">FinishFastBlitting</a></td><td width="65%" halign="center"><div class="smalltext">This function should be called after calling FastBlit</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/UnloadToMemory.html">UnloadToMemory</a></td><td width="65%" halign="center"><div class="smalltext">Unloads the Bitmap from the graphics card keeping the image data saved in the Bitmap</div></td></tr><tr><td halign="center" class="funclist"><a href="../Bitmap/TexturedQuad.html">TexturedQuad</a></td><td width="65%" halign="center"><div class="smalltext">Outputs a raw textured quad to the video card</div></td></tr></table></div><br><div class=""><a href="../index.html">Back to the main page of the manual</a></div><br>Questions about GetPixel? Click <a href="http://crystalstorm.ath.cx/index.php?lan=en&page=CreateFeedback&subject=GetPixel">here.</a></div></td></tr></table></body></html>
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