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我已經研究了幾天。看來大多數人想要將按鈕放在透明的畫布或外殼上。我需要在畫布/組件上放置透明的可點擊對象。在我的測試中，我發現如果我不試圖將對象放在畫布上，它就不會顯示。SWT透明按鈕/標籤
在最終的項目中，應用程序將顯示帶有多個控件的動畫對象，我計劃使用它們的圖像。
在這個例子中，我試圖找出我已經採取了Snipped195，它顯示了一個轉動圓環。我正試圖在圓環上放置圖像標籤，以便圓環轉動時它會透過標籤的透明區域顯示。我建立了一個GIF文件，它是一個紅色加號，並具有透明背景。我也選擇了一些代碼（不記得它從哪裏來），它是paintControl方法的一部分，它查找透明像素並構建一個Region對象。區域對象顯然正在做它需要做的事情來定義圖像的位置。我是否需要以某種方式將該區域應用於圖像而不是畫布？
起初，當我試圖做到這一點，我確實得到了圖像顯示。但是，透明區域顯示爲白色。在實現paintControl代碼之後，它至少可以正確處理透明區域。現在我需要獲取顯示的實際圖像內容。
我建立了一個對象來照顧圖像標籤。我稱之爲TransparentImageLabel。它看起來像：
public class TransparentImageLabel extends Canvas {
private Image labelImage;
public TransparentImageLabel(Composite parent, Image image, int style) {
super(parent, style);
this.labelImage = image;
addDisposeListener(new DisposeListener() {
public void widgetDisposed(DisposeEvent e) {
TransparentImageLabel.this.widgetDisposed(e);
}
});
addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
TransparentImageLabel.this.paintControl(e);
}
});
}
private void widgetDisposed(DisposeEvent e) {
}
private void paintControl(PaintEvent event) {
System.out.println("at paint control");
ImageData imgData = this.labelImage.getImageData();
Region region = new Region();
if (imgData.alphaData != null) {
Rectangle pixel = new Rectangle(0, 0, 1, 1);
for (int y = 0; y < imgData.height; y++) {
for (int x = 0; x < imgData.width; x++) {
if (imgData.getAlpha(x, y) == 255) {
pixel.x = imgData.x + x;
pixel.y = imgData.y + y;
region.add(pixel);
}
}
}
} else {
ImageData mask = imgData.getTransparencyMask();
Rectangle pixel = new Rectangle(0, 0, 1, 1);
for (int y = 0; y < mask.height; y++) {
for (int x = 0; x < mask.width; x++) {
if (mask.getPixel(x, y) != 0) {
pixel.x = imgData.x + x;
pixel.y = imgData.y + y;
region.add(pixel);
}
}
}
}
this.setRegion(region);
event.gc.drawImage(labelImage, this.getBounds().x, this.getBounds().y);
region.dispose();
}
}
加入這Snipped195後的代碼如下所示：
public class Snippet195 {
private Image redPlus;
static void drawTorus(float r, float R, int nsides, int rings) {
float ringDelta = 2.0f * (float) Math.PI/rings;
float sideDelta = 2.0f * (float) Math.PI/nsides;
float theta = 0.0f, cosTheta = 1.0f, sinTheta = 0.0f;
for (int i = rings - 1; i >= 0; i--) {
float theta1 = theta + ringDelta;
float cosTheta1 = (float) Math.cos(theta1);
float sinTheta1 = (float) Math.sin(theta1);
GL11.glBegin(GL11.GL_QUAD_STRIP);
float phi = 0.0f;
for (int j = nsides; j >= 0; j--) {
phi += sideDelta;
float cosPhi = (float) Math.cos(phi);
float sinPhi = (float) Math.sin(phi);
float dist = R + r * cosPhi;
GL11.glNormal3f(cosTheta1 * cosPhi, -sinTheta1 * cosPhi, sinPhi);
GL11.glVertex3f(cosTheta1 * dist, -sinTheta1 * dist, r * sinPhi);
GL11.glNormal3f(cosTheta * cosPhi, -sinTheta * cosPhi, sinPhi);
GL11.glVertex3f(cosTheta * dist, -sinTheta * dist, r * sinPhi);
}
GL11.glEnd();
theta = theta1;
cosTheta = cosTheta1;
sinTheta = sinTheta1;
}
}
private Snippet195() {
final Display display = new Display();
Shell shell = new Shell(display, SWT.NO_REDRAW_RESIZE);
shell.setLayout(new FillLayout());
Composite comp = new Composite(shell, SWT.NONE);
comp.setLayout(new FillLayout());
GLData data = new GLData();
data.doubleBuffer = true;
redPlus = new Image(shell.getDisplay(), new ImageData(
Snippet237.class.getResourceAsStream("/red-plus.png")));
final GLCanvas canvas = new GLCanvas(comp, SWT.NONE, data);
canvas.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
e.gc.setAlpha(15);
e.gc.drawImage(Snippet195.this.redPlus, 0, 0);
}
});
canvas.setCurrent();
try {
GLContext.useContext(canvas);
} catch (LWJGLException e) {
e.printStackTrace();
}
canvas.addListener(SWT.Resize, new Listener() {
public void handleEvent(Event event) {
Rectangle bounds = canvas.getBounds();
float fAspect = (float) bounds.width/(float) bounds.height;
canvas.setCurrent();
try {
GLContext.useContext(canvas);
} catch (LWJGLException e) {
e.printStackTrace();
}
GL11.glViewport(0, 0, bounds.width, bounds.height);
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glLoadIdentity();
GLU.gluPerspective(45.0f, fAspect, 0.5f, 400.0f);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glLoadIdentity();
}
});
GL11.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
GL11.glColor3f(1.0f, 0.0f, 0.0f);
GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST);
GL11.glClearDepth(1.0);
GL11.glLineWidth(2);
GL11.glEnable(GL11.GL_DEPTH_TEST);
TransparentImageLabel redPlusLabel = new TransparentImageLabel(canvas,
redPlus, SWT.NONE);
redPlusLabel.setSize(48, 48);
redPlusLabel.setLocation(500, 200);
shell.setText("SWT/LWJGL Example");
shell.setSize(880, 720);
shell.open();
final Runnable run = new Runnable() {
int rot = 0;
public void run() {
if (!canvas.isDisposed()) {
canvas.setCurrent();
try {
GLContext.useContext(canvas);
} catch (LWJGLException e) {
e.printStackTrace();
}
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT
| GL11.GL_DEPTH_BUFFER_BIT);
GL11.glClearColor(.3f, .5f, .8f, 1.0f);
GL11.glLoadIdentity();
GL11.glTranslatef(0.0f, 0.0f, -10.0f);
float frot = rot;
GL11.glRotatef(0.15f * rot, 2.0f * frot, 10.0f * frot, 1.0f);
GL11.glRotatef(0.3f * rot, 3.0f * frot, 1.0f * frot, 1.0f);
rot++;
GL11.glPolygonMode(GL11.GL_FRONT_AND_BACK, GL11.GL_LINE);
GL11.glColor3f(0.9f, 0.9f, 0.9f);
drawTorus(1, 1.9f + ((float) Math.sin((0.004f * frot))), 25, 75);
canvas.swapBuffers();
display.asyncExec(this);
}
}
};
canvas.addListener(SWT.Paint, new Listener() {
public void handleEvent(Event event) {
run.run();
}
});
display.asyncExec(run);
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
public static void main(String[] args) {
new Snippet195();
}
}
我必須靠近。被定義爲透明的圖像區域被繪製爲透明。但我沒有得到任何東西，只有白色加上，而不是圖像中的紅色。
你可以提供你正試圖繪製到畫布的透明圖像..？ – Sorceror