gecko-dev/mobile/android/base/gfx/ScrollbarLayer.java
Chris Lord cb9c55afb6 Bug 858969 - Refactor dynamic toolbar so page is offset and not overlapped. r=kats,nrc
Refactor the dynamic toolbar code so that the ownership of various properties
is clearer, and the page is offset by the toolbar instead of being overlapped.
This fixes problems with the scroll origin of the page not corresponding to
the visible origin on the screen.
2013-04-25 18:47:08 +01:00

296 lines
12 KiB
Java

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