LEADTOOLS Raster imaging C++ Class library help
| LEADTOOLS Raster Imaging C++ Class Library Help > LEADTOOLS Raster Imaging Features > Screen Capture > Used Structures > LEADCAPTUREOPTION |
typedef struct tagLEADCAPTUREOPTION
{
L_UINT uStructSize;
HCURSOR hCursor;
HCURSOR hStatusCursor;
L_INT nHotKey;
L_UINT uHotKeyModifiers;
L_INT nCancelKey;
L_INT nDelay;
L_UINT uCount;
L_INT nInterval;
L_UINT32 uFlags;
} LEADCAPTUREOPTION, * pLEADCAPTUREOPTION;
This structure is used in LScreenCapture::SetCaptureOptions and LScreenCapture::GetCaptureOptions to set/get the capture options.
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Member |
Description |
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uStructSize |
Size of this structure. Use sizeof (LAYERINFO). |
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hCursor |
Cursor to place on image after capture. Default is NULL. |
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hStatusCursor |
Cursor to display as status between multiple captures. Default is NULL. |
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nHotKey |
Key code for activation key. Default is F11. The user can immediately capture by setting the hot key to zero (0). |
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uHotKeyModifiers |
Modifier keys used with nHotKey. Possible values are listed below and may be combined. Default is 0. |
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MOD_ALT |
Alt Key pressed. |
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MOD_CONTROL |
Control key pressed. |
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MOD_SHIFT |
Shift key pressed. |
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0 |
No modifier key was pressed. |
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nCancelKey |
Key code for capture operation cancel key. Default is ESC. You cannot set this to the 'ALT' key (VK_MENU). If you do, it will be ignored internally and set to 'ESC' (VK_ESCAPE). |
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nDelay |
Milliseconds delay before capture. Default is 0. |
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uCount |
Number of times to capture. 0 or 1 means one capture, 2 means 2 captures, etc. Default is 1. |
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nInterval |
Milliseconds delay between captures. Default is 0 |
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uFlags |
Flag that indicates whether to optimize hotkey processing. Possible values are: |
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Value |
Meaning |
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0 |
[0x0000] Perform normal hot key processing. |
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CAPTURE_OPTIMIZED_HOTKEY |
[0x0001] Use a global system hook for hotkey processing. |
Comments
Normally, when a capture function is called, the function enters a loop, and waits for the hot key specified in nHotKey to be pressed, before capturing. This loop can cause the CPU usage indicator to appear maxed out. Specifying CAPTURE_OPTIMIZED_HOTKEY in uFlags will cause the capture function to return immediately, if a hotkey has been specified in nHotKey. In this case, a global system hotkey hook is established and used to wait for the hotkey to be pressed. When the hotkey is pressed, the capture is performed and the callback passed to the capture function is called with the result of the capture. Use this option only if the normal behavior is causing your application problems. This option is ignored in Win95/98/Me.
