Make TextArea.setCursorPosition work in all browsers (#8769)

svn changeset:25579/svn branch:6.8

Conflicts:
	client/src/com/vaadin/client/ui/VTextField.java

Change-Id: I3b53be8df4ce0564f34d8aa9bc1ce1c34648eadd

2 files changed, 118 insertions, 0 deletions

diff --git a/client/src/com/vaadin/client/ui/VTextArea.java b/client/src/com/vaadin/client/ui/VTextArea.java
index 4a5de23828..45e0532451 100644
--- a/client/src/com/vaadin/client/ui/VTextArea.java
+++ b/client/src/com/vaadin/client/ui/VTextArea.java
@@ -63,6 +63,120 @@ public class VTextArea extends VTextField {
         getTextAreaElement().setRows(rows);
     }
 
+    @Override
+    public void setSelectionRange(int pos, int length) {
+        super.setSelectionRange(pos, length);
+        final String value = getValue();
+        /*
+         * Align position to index inside string value
+         */
+        int index = pos;
+        if (index < 0) {
+            index = 0;
+        }
+        if (index > value.length()) {
+            index = value.length();
+        }
+        // Get pixels count required to scroll textarea vertically
+        int scrollTop = getScrollTop(value, index);
+        int scrollLeft = -1;
+        /*
+         * Check if textarea has wrap attribute set to "off". In the latter case
+         * horizontal scroll is also required.
+         */
+        if (!isWordwrap()) {
+            // Get pixels count required to scroll textarea horizontally
+            scrollLeft = getScrollLeft(value, index);
+        }
+        // Set back original text if previous methods calls changed it
+        if (!isWordwrap() || index < value.length()) {
+            setValue(value, false);
+        }
+        /*
+         * Call original method to set cursor position. In most browsers it
+         * doesn't lead to scrolling.
+         */
+        super.setSelectionRange(pos, length);
+        /*
+         * Align vertical scroll to middle of textarea view (height) if
+         * scrolling is reqiured at all.
+         */
+        if (scrollTop > 0) {
+            scrollTop += getElement().getClientHeight() / 2;
+        }
+        /*
+         * Align horizontal scroll to middle of textarea view (widht) if
+         * scrolling is reqiured at all.
+         */
+        if (scrollLeft > 0) {
+            scrollLeft += getElement().getClientWidth() / 2;
+        }
+        /*
+         * Scroll if computed scrollTop is greater than scroll after cursor
+         * setting
+         */
+        if (getElement().getScrollTop() < scrollTop) {
+            getElement().setScrollTop(scrollTop);
+        }
+        /*
+         * Scroll if computed scrollLeft is greater than scroll after cursor
+         * setting
+         */
+        if (getElement().getScrollLeft() < scrollLeft) {
+            getElement().setScrollLeft(scrollLeft);
+        }
+    }
+
+    /*
+     * Get horizontal scroll value required to get position visible. Method is
+     * called only when text wrapping is off. There is need to scroll
+     * horizontally in case words are wrapped.
+     */
+    private int getScrollLeft(String value, int index) {
+        String beginning = value.substring(0, index);
+        // Compute beginning of the current line
+        int begin = beginning.lastIndexOf('\n');
+        String line = value.substring(begin + 1);
+        index = index - begin - 1;
+        if (index < line.length()) {
+            index++;
+        }
+        line = line.substring(0, index);
+        /*
+         * Now <code>line</code> contains current line up to index position
+         */
+        setValue(line.trim(), false); // Set this line to the textarea.
+        /*
+         * Scroll textarea up to the end of the line (maximum possible
+         * horizontal scrolling value). Now the end line becomes visible.
+         */
+        getElement().setScrollLeft(getElement().getScrollWidth());
+        // Return resulting horizontal scrolling value.
+        return getElement().getScrollLeft();
+    }
+
+    /*
+     * Get vertical scroll value required to get position visible
+     */
+    private int getScrollTop(String value, int index) {
+        /*
+         * Trim text after position and set this trimmed text if index is not
+         * very end.
+         */
+        if (index < value.length()) {
+            String beginning = value.substring(0, index);
+            setValue(beginning, false);
+        }
+        /*
+         * Now textarea contains trimmed text and could be scrolled up to the
+         * top. Scroll it to maximum possible value to get end of the text
+         * visible.
+         */
+        getElement().setScrollTop(getElement().getScrollHeight());
+        // Return resulting vertical scrolling value.
+        return getElement().getScrollTop();
+    }
+
     private class MaxLengthHandler implements KeyUpHandler, ChangeHandler {
 
         @Override
diff --git a/client/src/com/vaadin/client/ui/VTextField.java b/client/src/com/vaadin/client/ui/VTextField.java
index 0fbed0dd90..da9445c811 100644
--- a/client/src/com/vaadin/client/ui/VTextField.java
+++ b/client/src/com/vaadin/client/ui/VTextField.java
@@ -446,4 +446,8 @@ public class VTextField extends TextBoxBase implements Field, ChangeHandler,
         this.inputPrompt = inputPrompt;
     }
 
+    protected boolean isWordwrap() {
+        String wrap = getElement().getAttribute("wrap");
+        return !"off".equals(wrap);
+    }
 }