opt: draw only visible chars for a line

app/build.gradle

@@ -8,8 +8,8 @@ android {
         applicationId "com.stardust.scriptdroid"
         minSdkVersion 17
         targetSdkVersion 23
-        versionCode 250
+        versionCode 251
-        versionName "3.0.0 Alpha50"
+        versionName "3.1.0 Alpha"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
         multiDexEnabled true
         ndk {

app/src/main/java/com/stardust/scriptdroid/ui/edit/editor/CodeEditText.java

@@ -23,11 +23,10 @@ import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Typeface;
 import android.support.v7.widget.AppCompatEditText;
-import android.text.Editable;
 import android.text.Layout;
 import android.util.AttributeSet;
-import android.util.Log;
 import android.view.Gravity;
+import android.view.View;
 
 import com.stardust.scriptdroid.ui.edit.theme.Theme;
 
@@ -128,7 +127,9 @@ public class CodeEditText extends AppCompatEditText {
         int fontCount = 0;
         int previousColor = mHighlightTokens.getCharColor(lineStart);
         int previousColorPos = lineStart;
-        for (int i = lineStart; i < lineEnd; i++) {
+        int visibleCharStart = getVisibleCharIndex(paint, getScrollX(), lineStart, lineEnd);
+        int visibleCharEnd = getVisibleCharIndex(paint, getScrollX() + getWidth(), lineStart, lineEnd) + 1;
+        for (int i = visibleCharStart; i < visibleCharEnd && i < lineEnd; i++) {
             fontCount++;
             int color = mHighlightTokens.getCharColor(i);
             if (previousColor != color) {
@@ -137,13 +138,30 @@ public class CodeEditText extends AppCompatEditText {
                 previousColorPos = i;
                 fontCount = 1;
             }
-            if (i == lineEnd - 1) {
+            if (i == visibleCharEnd - 1) {
                 drawText(canvas, paint, paddingLeft, lineBaseline, lineStart, previousColorPos, previousColorPos + fontCount, previousColor);
             }
         }
 
     }
 
+    private int getVisibleCharIndex(Paint paint, int x, int lineStart, int lineEnd) {
+        if (x == 0)
+            return lineStart;
+        int low = lineStart;
+        int high = lineEnd - 1;
+        while (low < high) {
+            int mid = (high + low) >>> 1;
+            float midX = paint.measureText(getText(), lineStart, mid + 1);
+            if (x < midX) {
+                high = mid - 1;
+            } else {
+                low = mid + 1;
+            }
+        }
+        return low;
+    }
+
     private void drawText(Canvas canvas, Paint paint, int paddingLeft, int lineBaseline, int lineStart, int start, int end, int color) {
         if (start >= end) {
             return;
@@ -162,16 +180,23 @@ public class CodeEditText extends AppCompatEditText {
 
     private long getLineRangeForDraw(Layout layout, Canvas canvas) {
         canvas.save();
-        float clipTop = (mScrollView.getScrollY() == 0) ? 0
+        int scrollY = getRealScrollY();
-                : getExtendedPaddingTop() + mScrollView.getScrollY()
+        float clipTop = (scrollY == 0) ? 0
+                : getExtendedPaddingTop() + scrollY
                 - mScrollView.getPaddingTop();
-        canvas.clipRect(0, clipTop, getWidth(), mScrollView.getScrollY()
+        canvas.clipRect(0, clipTop, getWidth(), scrollY
                 + mScrollView.getHeight());
         long lineRangeForDraw = LayoutHelper.getLineRangeForDraw(layout, canvas);
         canvas.restore();
         return lineRangeForDraw;
     }
 
+    private int getRealScrollY() {
+        int scrollY = mScrollView.getScrollY();
+        View parent = (View) mScrollView.getParent();
+        return scrollY + parent.getScrollY();
+    }
+
     @Override
     protected void onSelectionChanged(int selStart, int selEnd) {
         super.onSelectionChanged(selStart, selEnd);
@@ -206,7 +231,6 @@ public class CodeEditText extends AppCompatEditText {
 
     public void updateHighlightTokens(JavaScriptHighlighter.HighlightTokens highlightTokens) {
         mHighlightTokens = highlightTokens;
-        Log.d(LOG_TAG, "tokens = " + highlightTokens);
+        postInvalidate();
-        invalidate();
     }
 }

app/src/main/java/com/stardust/scriptdroid/ui/edit/editor/CodeEditor.java

@@ -35,10 +35,41 @@ import io.reactivex.Observable;
  */
 public class CodeEditor extends HVScrollView {
 
+    public interface CursorChangeCallback {
+
+        void onCursorChange(String line, int ch);
+
+    }
+
 
     private CharSequence mReplacement = "";
     private String mKeywords;
     private int mFoundIndex = -1;
+    private CodeEditText mCodeEditText;
+    private PreformEdit mPreformEdit;
+    private JavaScriptHighlighter mJavaScriptHighlighter;
+    private Theme mTheme;
+
+    public CodeEditor(Context context) {
+        super(context);
+        init();
+    }
+
+    public CodeEditor(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+
+    private void init() {
+        setFillViewport(true);
+        inflate(getContext(), R.layout.code_editor, this);
+        mCodeEditText = (CodeEditText) findViewById(R.id.code_edit_text);
+        mPreformEdit = new PreformEdit(mCodeEditText);
+        mJavaScriptHighlighter = new JavaScriptHighlighter(mTheme, mCodeEditText);
+        setTheme(Theme.getDefault(getContext()));
+
+    }
 
     public Observable<Integer> getLineCount() {
         return Observable.just(mCodeEditText.getLayout().getLineCount());
@@ -100,39 +131,6 @@ public class CodeEditor extends HVScrollView {
 
     }
 
-
-    public interface CursorChangeCallback {
-
-        void onCursorChange(String line, int ch);
-
-    }
-
-    private CodeEditText mCodeEditText;
-    private PreformEdit mPreformEdit;
-    private JavaScriptHighlighter mJavaScriptHighlighter;
-    private Theme mTheme;
-
-    public CodeEditor(Context context) {
-        super(context);
-        init();
-    }
-
-    public CodeEditor(Context context, AttributeSet attrs) {
-        super(context, attrs);
-        init();
-    }
-
-
-    private void init() {
-        setFillViewport(true);
-        inflate(getContext(), R.layout.code_editor, this);
-        mCodeEditText = (CodeEditText) findViewById(R.id.code_edit_text);
-        mPreformEdit = new PreformEdit(mCodeEditText);
-        mJavaScriptHighlighter = new JavaScriptHighlighter(mTheme, mCodeEditText);
-        setTheme(Theme.getDefault(getContext()));
-
-    }
-
     public void setTheme(Theme theme) {
         mTheme = theme;
         mJavaScriptHighlighter.setTheme(theme);

app/src/main/java/com/stardust/scriptdroid/ui/edit/editor/JavaScriptHighlighter.java

@@ -24,6 +24,7 @@ public class JavaScriptHighlighter implements SimpleTextWatcher.AfterTextChanged
 
         private int[] mColors;
         private String mText;
+        private int mCount;
 
         public HighlightTokens(String text) {
             mColors = new int[text.length()];
@@ -40,6 +41,7 @@ public class JavaScriptHighlighter implements SimpleTextWatcher.AfterTextChanged
             for (int i = tokenStart; i < tokenEnd; i++) {
                 mColors[i] = color;
             }
+            mCount = tokenEnd;
         }
 
         @Override
@@ -50,7 +52,7 @@ public class JavaScriptHighlighter implements SimpleTextWatcher.AfterTextChanged
         }
 
         public int getCharCount() {
-            return mColors.length;
+            return mCount;
         }
 
         public String getText() {
@@ -101,9 +103,10 @@ public class JavaScriptHighlighter implements SimpleTextWatcher.AfterTextChanged
             int color = mTheme.getColorForToken(token);
             highlightTokens.addToken(ts.getTokenBeg(), ts.getTokenEnd(), color);
         }
+        if (highlightTokens.getCharCount() < sourceString.length()) {
+            highlightTokens.addToken(highlightTokens.getCharCount(), sourceString.length(), mTheme.getColorForToken(Token.NAME));
+        }
         mCodeEditText.updateHighlightTokens(highlightTokens);
-        Log.d("Highlighter", "code = " + sourceString);
-        Log.d("Highlighter", "tokens = " + highlightTokens);
     }