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我在一個項目中需要使用Java和JavaFX的vtk。爲了給VTK提供正確的畫布,我想知道GetDrawingSurface()函數在下面的代碼中做了什麼。 awt是jawt庫中jawt.h中描述的JAWT對象。AWT.GetDrawingSurface是做什麼的?
這是爲了重寫一個Java類,爲C++提供正確的畫布。
extern "C" JNIEXPORT jint JNICALL
Java_vtk_vtkPanel_RenderCreate(JNIEnv *env, jobject canvas, jobject id0)
{
#if defined(WIN32_JAWT_LOCK_HACK)
int hash;
WJLH_HASH_FUNC(env, canvas, hash);
WJLH_lock_map[hash] = 0;
#endif
JAWT awt;
JAWT_DrawingSurface* ds;
JAWT_DrawingSurfaceInfo* dsi;
jint lock;
// get the render window pointer
vtkRenderWindow *temp0;
temp0 = (vtkRenderWindow *)(vtkJavaGetPointerFromObject(env,id0));
/* Get the AWT */
awt.version = JAWT_VERSION_1_3;
if (JAWT_GetAWT(env, &awt) == JNI_FALSE)
{
#ifndef VTK_JAVA_DEBUG
printf("AWT Not found\n");
#endif
return 1;
}
/* Get the drawing surface */
ds = awt.GetDrawingSurface(env, canvas);
if (ds == NULL)
{
#ifndef VTK_JAVA_DEBUG
printf("NULL drawing surface\n");
#endif
return 1;
}
/* Lock the drawing surface */
lock = ds->Lock(ds);
if((lock & JAWT_LOCK_ERROR) != 0)
{
#ifndef VTK_JAVA_DEBUG
printf("Error locking surface\n");
#endif
awt.FreeDrawingSurface(ds);
return 1;
}
/* Get the drawing surface info */
dsi = ds->GetDrawingSurfaceInfo(ds);
if (dsi == NULL)
{
printf("Error getting surface info\n");
ds->Unlock(ds);
awt.FreeDrawingSurface(ds);
return 1;
}
// Here is the win32 drawing code
#if defined(_WIN32) || defined(WIN32)
temp0->Finalize();
JAWT_Win32DrawingSurfaceInfo* dsi_win;
dsi_win = (JAWT_Win32DrawingSurfaceInfo*)dsi->platformInfo;
temp0->SetWindowId((void *)dsi_win->hwnd);
temp0->SetDisplayId((void *)dsi_win->hdc);
// also set parent id to avoid border sizes being added
temp0->SetParentId((void *)dsi_win->hdc);
// use mac code
#elif defined(__APPLE__)
JAWT_MacOSXDrawingSurfaceInfo* dsi_mac;
dsi_mac = (JAWT_MacOSXDrawingSurfaceInfo*)dsi->platformInfo;
temp0->SetWindowId(dsi_mac->cocoaViewRef);
// otherwise use X11 code
#else
JAWT_X11DrawingSurfaceInfo* dsi_x11;
dsi_x11 = (JAWT_X11DrawingSurfaceInfo*)dsi->platformInfo;
temp0->SetDisplayId((void *)dsi_x11->display);
temp0->SetWindowId((void *)dsi_x11->drawable);
temp0->SetParentId((void *)dsi_x11->display);
#endif
/* Free the drawing surface info */
ds->FreeDrawingSurfaceInfo(dsi);
/* Unlock the drawing surface */
ds->Unlock(ds);
/* Free the drawing surface */
awt.FreeDrawingSurface(ds);
#if defined(WIN32_JAWT_LOCK_HACK)
if (WJLH_init_check == 0)
{
WJLH_init_check = 1;
}
WJLH_lock_map[hash] = 1;
#endif
return 0;
}