如何通过辅助功能 API 获取当前选定文本的全局屏幕坐标. [英] How to get global screen coordinates of currently selected text via Accessibility APIs.

问题描述

我需要帮助找出在任何应用程序上按 CMD+CTRL+D 时，字典应用程序如何为所选文本显示以下弹出对话框.我想实施与我的可可应用程序相同的功能，我的应用程序将在后台运行并显示有关所选文本的某些热键按下的建议.

I need help to find out, how Dictionary app showing following popup dialog for selected text on pressing CMD+CTRL+D on any application. I want to implement the same kind of functionality for my cocoa app, where my app will run in background and showing suggestions on some hot key press for the selected text.

我已经实现了热键捕获，我只需要编写代码来获取屏幕上所选文本的矩形区域，这样我就可以像字典应用程序一样显示对话框.

I have already implemented hot key capturing, i just need to have code to get the rectangle area of selected text on screen, so i can show the dialog like dictionary app.

谢谢

推荐答案

您可以为此使用辅助功能 API.确保选中启用辅助设备访问"设置(在系统偏好设置/通用访问中).

You can use the accessibility APIs for that. Make sure that the "Enable access for assistive devices" setting is checked (in System Preferences / Universal Access).

以下代码片段将确定大多数应用程序中所选文本的边界(以屏幕坐标表示).不幸的是，它在 Mail 和 Safari 中不起作用，因为它们使用私有的可访问性属性.也有可能让它在那里工作，但它需要更多的工作和可能的私有 API 调用.

The following code snippet will determine the bounds (in screen coordinates) of the selected text in most applications. Unfortunately, it doesn't work in Mail and Safari, because they use private accessibility attributes. It's probably possible to get it to work there as well, but it requires more work and possibly private API calls.

AXUIElementRef systemWideElement = AXUIElementCreateSystemWide();
AXUIElementRef focussedElement = NULL;
AXError error = AXUIElementCopyAttributeValue(systemWideElement, kAXFocusedUIElementAttribute, (CFTypeRef *)&focussedElement);
if (error != kAXErrorSuccess) {
    NSLog(@"Could not get focussed element");
} else {
    AXValueRef selectedRangeValue = NULL;
    AXError getSelectedRangeError = AXUIElementCopyAttributeValue(focussedElement, kAXSelectedTextRangeAttribute, (CFTypeRef *)&selectedRangeValue);
    if (getSelectedRangeError == kAXErrorSuccess) {
        CFRange selectedRange;
        AXValueGetValue(selectedRangeValue, kAXValueCFRangeType, &selectedRange);
        AXValueRef selectionBoundsValue = NULL;
        AXError getSelectionBoundsError = AXUIElementCopyParameterizedAttributeValue(focussedElement, kAXBoundsForRangeParameterizedAttribute, selectedRangeValue, (CFTypeRef *)&selectionBoundsValue);
        CFRelease(selectedRangeValue);
        if (getSelectionBoundsError == kAXErrorSuccess) {
            CGRect selectionBounds;
            AXValueGetValue(selectionBoundsValue, kAXValueCGRectType, &selectionBounds);
            NSLog(@"Selection bounds: %@", NSStringFromRect(NSRectFromCGRect(selectionBounds)));
        } else {
            NSLog(@"Could not get bounds for selected range");
        }
        if (selectionBoundsValue != NULL) CFRelease(selectionBoundsValue);
    } else {
        NSLog(@"Could not get selected range");
    }
}
if (focussedElement != NULL) CFRelease(focussedElement);
CFRelease(systemWideElement);

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