michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.gfx;
michael@0: 
michael@0: import org.mozilla.gecko.util.FloatUtils;
michael@0: 
michael@0: import android.graphics.Bitmap;
michael@0: import android.graphics.Rect;
michael@0: import android.graphics.RectF;
michael@0: import android.opengl.GLES20;
michael@0: 
michael@0: import java.nio.FloatBuffer;
michael@0: 
michael@0: public class ScrollbarLayer extends TileLayer {
michael@0:     public static final long FADE_DELAY = 500; // milliseconds before fade-out starts
michael@0:     private static final float FADE_AMOUNT = 0.03f; // how much (as a percent) the scrollbar should fade per frame
michael@0: 
michael@0:     private final boolean mVertical;
michael@0:     private float mOpacity;
michael@0: 
michael@0:     // To avoid excessive GC, declare some objects here that would otherwise
michael@0:     // be created and destroyed frequently during draw().
michael@0:     private final RectF mBarRectF;
michael@0:     private final Rect mBarRect;
michael@0:     private final float[] mCoords;
michael@0:     private final RectF mCapRectF;
michael@0: 
michael@0:     private LayerRenderer mRenderer;
michael@0:     private int mProgram;
michael@0:     private int mPositionHandle;
michael@0:     private int mTextureHandle;
michael@0:     private int mSampleHandle;
michael@0:     private int mTMatrixHandle;
michael@0:     private int mOpacityHandle;
michael@0: 
michael@0:     // Fragment shader used to draw the scroll-bar with opacity
michael@0:     private static final String FRAGMENT_SHADER =
michael@0:         "precision mediump float;\n" +
michael@0:         "varying vec2 vTexCoord;\n" +
michael@0:         "uniform sampler2D sTexture;\n" +
michael@0:         "uniform float uOpacity;\n" +
michael@0:         "void main() {\n" +
michael@0:         "    gl_FragColor = texture2D(sTexture, vTexCoord);\n" +
michael@0:         "    gl_FragColor.a *= uOpacity;\n" +
michael@0:         "}\n";
michael@0: 
michael@0:     // Dimensions of the texture bitmap (will always be power-of-two)
michael@0:     private final int mTexWidth;
michael@0:     private final int mTexHeight;
michael@0:     // Some useful dimensions of the actual content in the bitmap
michael@0:     private final int mBarWidth;
michael@0:     private final int mCapLength;
michael@0: 
michael@0:     private final Rect mStartCapTexCoords;  // top/left endcap coordinates
michael@0:     private final Rect mBodyTexCoords;      // 1-pixel slice of the texture to be stretched
michael@0:     private final Rect mEndCapTexCoords;    // bottom/right endcap coordinates
michael@0: 
michael@0:     ScrollbarLayer(LayerRenderer renderer, Bitmap scrollbarImage, IntSize imageSize, boolean vertical) {
michael@0:         super(new BufferedCairoImage(scrollbarImage), TileLayer.PaintMode.NORMAL);
michael@0:         mRenderer = renderer;
michael@0:         mVertical = vertical;
michael@0: 
michael@0:         mBarRectF = new RectF();
michael@0:         mBarRect = new Rect();
michael@0:         mCoords = new float[20];
michael@0:         mCapRectF = new RectF();
michael@0: 
michael@0:         mTexHeight = scrollbarImage.getHeight();
michael@0:         mTexWidth = scrollbarImage.getWidth();
michael@0: 
michael@0:         if (mVertical) {
michael@0:             mBarWidth = imageSize.width;
michael@0:             mCapLength = imageSize.height / 2;
michael@0:             mStartCapTexCoords = new Rect(0, mTexHeight - mCapLength, imageSize.width, mTexHeight);
michael@0:             mBodyTexCoords = new Rect(0, mTexHeight - (mCapLength + 1), imageSize.width, mTexHeight - mCapLength);
michael@0:             mEndCapTexCoords = new Rect(0, mTexHeight - imageSize.height, imageSize.width, mTexHeight - (mCapLength + 1));
michael@0:         } else {
michael@0:             mBarWidth = imageSize.height;
michael@0:             mCapLength = imageSize.width / 2;
michael@0:             mStartCapTexCoords = new Rect(0, mTexHeight - imageSize.height, mCapLength, mTexHeight);
michael@0:             mBodyTexCoords = new Rect(mCapLength, mTexHeight - imageSize.height, mCapLength + 1, mTexHeight);
michael@0:             mEndCapTexCoords = new Rect(mCapLength + 1, mTexHeight - imageSize.height, imageSize.width, mTexHeight);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     private void createProgram() {
michael@0:         int vertexShader = LayerRenderer.loadShader(GLES20.GL_VERTEX_SHADER,
michael@0:                                                     LayerRenderer.DEFAULT_VERTEX_SHADER);
michael@0:         int fragmentShader = LayerRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER,
michael@0:                                                       FRAGMENT_SHADER);
michael@0: 
michael@0:         mProgram = GLES20.glCreateProgram();
michael@0:         GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
michael@0:         GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
michael@0:         GLES20.glLinkProgram(mProgram);                  // creates OpenGL program executables
michael@0: 
michael@0:         // Get handles to the shaders' vPosition, aTexCoord, sTexture, and uTMatrix members.
michael@0:         mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
michael@0:         mTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTexCoord");
michael@0:         mSampleHandle = GLES20.glGetUniformLocation(mProgram, "sTexture");
michael@0:         mTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uTMatrix");
michael@0:         mOpacityHandle = GLES20.glGetUniformLocation(mProgram, "uOpacity");
michael@0:     }
michael@0: 
michael@0:     private void activateProgram() {
michael@0:         // Add the program to the OpenGL environment
michael@0:         GLES20.glUseProgram(mProgram);
michael@0: 
michael@0:         // Set the transformation matrix
michael@0:         GLES20.glUniformMatrix4fv(mTMatrixHandle, 1, false,
michael@0:                                   LayerRenderer.DEFAULT_TEXTURE_MATRIX, 0);
michael@0: 
michael@0:         // Enable the arrays from which we get the vertex and texture coordinates
michael@0:         GLES20.glEnableVertexAttribArray(mPositionHandle);
michael@0:         GLES20.glEnableVertexAttribArray(mTextureHandle);
michael@0: 
michael@0:         GLES20.glUniform1i(mSampleHandle, 0);
michael@0:         GLES20.glUniform1f(mOpacityHandle, mOpacity);
michael@0:     }
michael@0: 
michael@0:     private void deactivateProgram() {
michael@0:         GLES20.glDisableVertexAttribArray(mTextureHandle);
michael@0:         GLES20.glDisableVertexAttribArray(mPositionHandle);
michael@0:         GLES20.glUseProgram(0);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Decrease the opacity of the scrollbar by one frame's worth.
michael@0:      * Return true if the opacity was decreased, or false if the scrollbars
michael@0:      * are already fully faded out.
michael@0:      */
michael@0:     public boolean fade() {
michael@0:         if (FloatUtils.fuzzyEquals(mOpacity, 0.0f)) {
michael@0:             return false;
michael@0:         }
michael@0:         beginTransaction(); // called on compositor thread
michael@0:         mOpacity = Math.max(mOpacity - FADE_AMOUNT, 0.0f);
michael@0:         endTransaction();
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Restore the opacity of the scrollbar to fully opaque.
michael@0:      * Return true if the opacity was changed, or false if the scrollbars
michael@0:      * are already fully opaque.
michael@0:      */
michael@0:     public boolean unfade() {
michael@0:         if (FloatUtils.fuzzyEquals(mOpacity, 1.0f)) {
michael@0:             return false;
michael@0:         }
michael@0:         beginTransaction(); // called on compositor thread
michael@0:         mOpacity = 1.0f;
michael@0:         endTransaction();
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     public void draw(RenderContext context) {
michael@0:         if (!initialized())
michael@0:             return;
michael@0: 
michael@0:         // Create the shader program, if necessary
michael@0:         if (mProgram == 0) {
michael@0:             createProgram();
michael@0:         }
michael@0: 
michael@0:         // Enable the shader program
michael@0:         mRenderer.deactivateDefaultProgram();
michael@0:         activateProgram();
michael@0: 
michael@0:         GLES20.glEnable(GLES20.GL_BLEND);
michael@0:         GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
michael@0: 
michael@0:         if (mVertical) {
michael@0:             getVerticalRect(context, mBarRectF);
michael@0:         } else {
michael@0:             getHorizontalRect(context, mBarRectF);
michael@0:         }
michael@0:         RectUtils.round(mBarRectF, mBarRect);
michael@0: 
michael@0:         GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
michael@0:         GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, getTextureID());
michael@0: 
michael@0:         float viewWidth = context.viewport.width();
michael@0:         float viewHeight = context.viewport.height();
michael@0: 
michael@0:         mBarRectF.set(mBarRect.left, viewHeight - mBarRect.top, mBarRect.right, viewHeight - mBarRect.bottom);
michael@0:         mBarRectF.offset(context.offset.x, -context.offset.y);
michael@0: 
michael@0:         // We take a 1-pixel slice from the center of the image and scale it to become the bar
michael@0:         fillRectCoordBuffer(mCoords, mBarRectF, viewWidth, viewHeight, mBodyTexCoords, mTexWidth, mTexHeight);
michael@0: 
michael@0:         // Get the buffer and handles from the context
michael@0:         FloatBuffer coordBuffer = context.coordBuffer;
michael@0:         int positionHandle = mPositionHandle;
michael@0:         int textureHandle = mTextureHandle;
michael@0: 
michael@0:         // Make sure we are at position zero in the buffer in case other draw methods did not
michael@0:         // clean up after themselves
michael@0:         coordBuffer.position(0);
michael@0:         coordBuffer.put(mCoords);
michael@0: 
michael@0:         // Unbind any the current array buffer so we can use client side buffers
michael@0:         GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
michael@0: 
michael@0:         // Vertex coordinates are x,y,z starting at position 0 into the buffer.
michael@0:         coordBuffer.position(0);
michael@0:         GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
michael@0:         coordBuffer.position(3);
michael@0:         GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
michael@0: 
michael@0:         // Reset the position in the buffer for the next set of vertex and texture coordinates.
michael@0:         coordBuffer.position(0);
michael@0:         if (mVertical) {
michael@0:             // top endcap
michael@0:             mCapRectF.set(mBarRectF.left, mBarRectF.top + mCapLength, mBarRectF.right, mBarRectF.top);
michael@0:         } else {
michael@0:             // left endcap
michael@0:             mCapRectF.set(mBarRectF.left - mCapLength, mBarRectF.bottom + mBarWidth, mBarRectF.left, mBarRectF.bottom);
michael@0:         }
michael@0: 
michael@0:         fillRectCoordBuffer(mCoords, mCapRectF, viewWidth, viewHeight, mStartCapTexCoords, mTexWidth, mTexHeight);
michael@0:         coordBuffer.put(mCoords);
michael@0: 
michael@0:         // Vertex coordinates are x,y,z starting at position 0 into the buffer.
michael@0:         coordBuffer.position(0);
michael@0:         GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
michael@0:         coordBuffer.position(3);
michael@0:         GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
michael@0: 
michael@0:         // Reset the position in the buffer for the next set of vertex and texture coordinates.
michael@0:         coordBuffer.position(0);
michael@0:         if (mVertical) {
michael@0:             // bottom endcap
michael@0:             mCapRectF.set(mBarRectF.left, mBarRectF.bottom, mBarRectF.right, mBarRectF.bottom - mCapLength);
michael@0:         } else {
michael@0:             // right endcap
michael@0:             mCapRectF.set(mBarRectF.right, mBarRectF.bottom + mBarWidth, mBarRectF.right + mCapLength, mBarRectF.bottom);
michael@0:         }
michael@0:         fillRectCoordBuffer(mCoords, mCapRectF, viewWidth, viewHeight, mEndCapTexCoords, mTexWidth, mTexHeight);
michael@0:         coordBuffer.put(mCoords);
michael@0: 
michael@0:         // Vertex coordinates are x,y,z starting at position 0 into the buffer.
michael@0:         coordBuffer.position(0);
michael@0:         GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
michael@0:         coordBuffer.position(3);
michael@0:         GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
michael@0: 
michael@0:         GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
michael@0: 
michael@0:         // Reset the position in the buffer for the next set of vertex and texture coordinates.
michael@0:         coordBuffer.position(0);
michael@0: 
michael@0:         // Enable the default shader program again
michael@0:         deactivateProgram();
michael@0:         mRenderer.activateDefaultProgram();
michael@0:     }
michael@0: 
michael@0:     private void getVerticalRect(RenderContext context, RectF dest) {
michael@0:         RectF viewport = context.viewport;
michael@0:         RectF pageRect = context.pageRect;
michael@0:         float viewportHeight = viewport.height() - context.offset.y;
michael@0:         float barStart = ((viewport.top - context.offset.y - pageRect.top) * (viewportHeight / pageRect.height())) + mCapLength;
michael@0:         float barEnd = ((viewport.bottom - context.offset.y - pageRect.top) * (viewportHeight / pageRect.height())) - mCapLength;
michael@0:         if (barStart > barEnd) {
michael@0:             float middle = (barStart + barEnd) / 2.0f;
michael@0:             barStart = barEnd = middle;
michael@0:         }
michael@0:         dest.set(viewport.width() - mBarWidth, barStart, viewport.width(), barEnd);
michael@0:     }
michael@0: 
michael@0:     private void getHorizontalRect(RenderContext context, RectF dest) {
michael@0:         RectF viewport = context.viewport;
michael@0:         RectF pageRect = context.pageRect;
michael@0:         float viewportWidth = viewport.width() - context.offset.x;
michael@0:         float barStart = ((viewport.left - context.offset.x - pageRect.left) * (viewport.width() / pageRect.width())) + mCapLength;
michael@0:         float barEnd = ((viewport.right - context.offset.x - pageRect.left) * (viewport.width() / pageRect.width())) - mCapLength;
michael@0:         if (barStart > barEnd) {
michael@0:             float middle = (barStart + barEnd) / 2.0f;
michael@0:             barStart = barEnd = middle;
michael@0:         }
michael@0:         dest.set(barStart, viewport.height() - mBarWidth, barEnd, viewport.height());
michael@0:     }
michael@0: }