gdi闪烁 [英] gdi flickering
问题描述
我使用全局GraphicsPath
变量为我的c ++类创建了一个绘图程序。在onpaint方法中，用鼠标绘制用户绘制的线条。简单。唯一的问题是，当我使面板无效时，为了看到线条而无法使用
，它会闪烁，即使是双缓冲也是如此。
如果我只使一个矩形无效在鼠标周围，如果用户将鼠标鼠标移得过快，那么该行不会在某些时间间隔内被绘制，因为油漆
事件无法激活足够多次。我怎样才能消除闪烁或
使panle的一部分无效，以便在
抽奖时间显示整行。 （如果我在面板前带任何东西或最小化
程序，windows重绘方法显示图形）
i也尝试使用Graphics变量来在mousedown
事件的表面上绘制，但是如果你最小化程序或在图形前面带来任何东西，你就会失去你画的东西。我怎么能发生这种情况呢？
哪个问题更容易回答，如果有的话，会有所帮助。我已经花了几周时间研究这个，但我似乎无法找到答案，谢谢
-
-iwdu15
i created a paint program for my c++ class using a global GraphicsPath
variable. i the, in the onpaint method, draw the line the users draws with
the mouse. simple. the only problem is that when i invalidate the panel im
drawing on in order to see the line, it flickers, even with double buffering.
if i only invalidate a rectangle around teh mouse, if the user mouse the
mouse too fast the line wont be drawn in certain intervals because the paint
event cant fire enough times. how can i either eliminate the flickering or
invalidate a part of the panle enough that it will show the entire line at
draw time. (if i bring anything in front of the panel or minimize the
program, the windows repaint method shows the graphics)
i also tried using a Graphics variable to draw on a surface on a mousedown
event, but then if you minimized the program or brought anything in front of
the graphics, youd lose what you drew. how can i sto this from happeneing?
which ever question is easier to answer, if any, would be helpful. ive been
researching this for weeks but i cant seem to find an answer, thanks
--
-iwdu15
推荐答案
iwdu15写道：
iwdu15 wrote:
我使用全局GraphicsPath
变量为我的c ++类创建了一个绘图程序。在onpaint方法中，绘制用户使用鼠标绘制的线条。简单。唯一的问题是，当我为了看到线条而无法使用面板时，它会闪烁，即使是双缓冲也是如此。
如果我只是使鼠标周围的矩形无效，如果是用户鼠标鼠标太快，线条不能在一定的时间间隔内绘制，因为油漆事件不能激发足够的时间。我怎样才能消除闪烁或
使一部分panle无效，以便在绘制时间显示整行。 （如果我在面板前带任何东西或最小化
程序，windows重绘方法显示图形）
我也尝试使用Graphics变量在mousedown上绘制一个表面
事件，但如果你最小化程序或在图形前带来任何东西，你就会失去你所画的东西。我怎么能发生这种情况呢？
哪个问题更容易回答，如果有的话，会有所帮助。我已经好好研究了几个星期，但我似乎无法找到答案，谢谢
i created a paint program for my c++ class using a global GraphicsPath
variable. i the, in the onpaint method, draw the line the users draws with
the mouse. simple. the only problem is that when i invalidate the panel im
drawing on in order to see the line, it flickers, even with double buffering.
if i only invalidate a rectangle around teh mouse, if the user mouse the
mouse too fast the line wont be drawn in certain intervals because the paint
event cant fire enough times. how can i either eliminate the flickering or
invalidate a part of the panle enough that it will show the entire line at
draw time. (if i bring anything in front of the panel or minimize the
program, the windows repaint method shows the graphics)
i also tried using a Graphics variable to draw on a surface on a mousedown
event, but then if you minimized the program or brought anything in front of
the graphics, youd lose what you drew. how can i sto this from happeneing?
which ever question is easier to answer, if any, would be helpful. ive been
researching this for weeks but i cant seem to find an answer, thanks
iwdu15：
您可能需要对WM_ERASEBKGND消息执行某些操作。通常做的是
通常从处理程序返回TRUE并在OnPaint（）中绘制所有内容，包括背景的
。
HTH，
David Wilkinson
iwdu15:
You probably need to do something with the WM_ERASEBKGND message. What I
usually do is return TRUE from the handler and draw everything,
including the backround, in OnPaint().
HTH,
David Wilkinson
我该怎么做？什么是WM_ERASEBKGND消息...感谢
你的帮助
-
-iwdu15
how would i do that? and what is "the WM_ERASEBKGND message"...thanks for
your help
--
-iwdu15
iwdu15写道：
iwdu15 wrote:
我该怎么做？什么是WM_ERASEBKGND消息...感谢您的帮助
how would i do that? and what is "the WM_ERASEBKGND message"...thanks for
your help
iwdu15：
如果这是一个Win32或MFC应用程序，这是一个Windows消息，如任何
其他。对于MFC，您可以通过在ClassView中选择相应的
类并选择Properties->事件来添加消息处理程序。
如果这是一个.NET应用程序然后我的建议可能不相关。
您需要请别人帮助您。
David Wilkinson
iwdu15:
If this is a Win32 or MFC application this is a Windows message like any
other. For MFC you can add message handlers by going to the appropriate
class in ClassView and Selecting Properties->Events.
If this is a .NET application then my suggestion may not be relevant.
You will need to ask someone else to help you.
David Wilkinson
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