mobile/android/base/gfx/ScrollbarLayer.java@b8a032363ba2
mobile/android/base/gfx/ScrollbarLayer.java
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
1 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
2 * This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 package org.mozilla.gecko.gfx;
8 import org.mozilla.gecko.util.FloatUtils;
10 import android.graphics.Bitmap;
11 import android.graphics.Rect;
12 import android.graphics.RectF;
13 import android.opengl.GLES20;
15 import java.nio.FloatBuffer;
17 public class ScrollbarLayer extends TileLayer {
18 public static final long FADE_DELAY = 500; // milliseconds before fade-out starts
19 private static final float FADE_AMOUNT = 0.03f; // how much (as a percent) the scrollbar should fade per frame
21 private final boolean mVertical;
22 private float mOpacity;
24 // To avoid excessive GC, declare some objects here that would otherwise
25 // be created and destroyed frequently during draw().
26 private final RectF mBarRectF;
27 private final Rect mBarRect;
28 private final float[] mCoords;
29 private final RectF mCapRectF;
31 private LayerRenderer mRenderer;
32 private int mProgram;
33 private int mPositionHandle;
34 private int mTextureHandle;
35 private int mSampleHandle;
36 private int mTMatrixHandle;
37 private int mOpacityHandle;
39 // Fragment shader used to draw the scroll-bar with opacity
40 private static final String FRAGMENT_SHADER =
41 "precision mediump float;\n" +
42 "varying vec2 vTexCoord;\n" +
43 "uniform sampler2D sTexture;\n" +
44 "uniform float uOpacity;\n" +
45 "void main() {\n" +
46 " gl_FragColor = texture2D(sTexture, vTexCoord);\n" +
47 " gl_FragColor.a *= uOpacity;\n" +
48 "}\n";
50 // Dimensions of the texture bitmap (will always be power-of-two)
51 private final int mTexWidth;
52 private final int mTexHeight;
53 // Some useful dimensions of the actual content in the bitmap
54 private final int mBarWidth;
55 private final int mCapLength;
57 private final Rect mStartCapTexCoords; // top/left endcap coordinates
58 private final Rect mBodyTexCoords; // 1-pixel slice of the texture to be stretched
59 private final Rect mEndCapTexCoords; // bottom/right endcap coordinates
61 ScrollbarLayer(LayerRenderer renderer, Bitmap scrollbarImage, IntSize imageSize, boolean vertical) {
62 super(new BufferedCairoImage(scrollbarImage), TileLayer.PaintMode.NORMAL);
63 mRenderer = renderer;
64 mVertical = vertical;
66 mBarRectF = new RectF();
67 mBarRect = new Rect();
68 mCoords = new float[20];
69 mCapRectF = new RectF();
71 mTexHeight = scrollbarImage.getHeight();
72 mTexWidth = scrollbarImage.getWidth();
74 if (mVertical) {
75 mBarWidth = imageSize.width;
76 mCapLength = imageSize.height / 2;
77 mStartCapTexCoords = new Rect(0, mTexHeight - mCapLength, imageSize.width, mTexHeight);
78 mBodyTexCoords = new Rect(0, mTexHeight - (mCapLength + 1), imageSize.width, mTexHeight - mCapLength);
79 mEndCapTexCoords = new Rect(0, mTexHeight - imageSize.height, imageSize.width, mTexHeight - (mCapLength + 1));
80 } else {
81 mBarWidth = imageSize.height;
82 mCapLength = imageSize.width / 2;
83 mStartCapTexCoords = new Rect(0, mTexHeight - imageSize.height, mCapLength, mTexHeight);
84 mBodyTexCoords = new Rect(mCapLength, mTexHeight - imageSize.height, mCapLength + 1, mTexHeight);
85 mEndCapTexCoords = new Rect(mCapLength + 1, mTexHeight - imageSize.height, imageSize.width, mTexHeight);
86 }
87 }
89 private void createProgram() {
90 int vertexShader = LayerRenderer.loadShader(GLES20.GL_VERTEX_SHADER,
91 LayerRenderer.DEFAULT_VERTEX_SHADER);
92 int fragmentShader = LayerRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER,
93 FRAGMENT_SHADER);
95 mProgram = GLES20.glCreateProgram();
96 GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
97 GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
98 GLES20.glLinkProgram(mProgram); // creates OpenGL program executables
100 // Get handles to the shaders' vPosition, aTexCoord, sTexture, and uTMatrix members.
101 mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
102 mTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTexCoord");
103 mSampleHandle = GLES20.glGetUniformLocation(mProgram, "sTexture");
104 mTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uTMatrix");
105 mOpacityHandle = GLES20.glGetUniformLocation(mProgram, "uOpacity");
106 }
108 private void activateProgram() {
109 // Add the program to the OpenGL environment
110 GLES20.glUseProgram(mProgram);
112 // Set the transformation matrix
113 GLES20.glUniformMatrix4fv(mTMatrixHandle, 1, false,
114 LayerRenderer.DEFAULT_TEXTURE_MATRIX, 0);
116 // Enable the arrays from which we get the vertex and texture coordinates
117 GLES20.glEnableVertexAttribArray(mPositionHandle);
118 GLES20.glEnableVertexAttribArray(mTextureHandle);
120 GLES20.glUniform1i(mSampleHandle, 0);
121 GLES20.glUniform1f(mOpacityHandle, mOpacity);
122 }
124 private void deactivateProgram() {
125 GLES20.glDisableVertexAttribArray(mTextureHandle);
126 GLES20.glDisableVertexAttribArray(mPositionHandle);
127 GLES20.glUseProgram(0);
128 }
130 /**
131 * Decrease the opacity of the scrollbar by one frame's worth.
132 * Return true if the opacity was decreased, or false if the scrollbars
133 * are already fully faded out.
134 */
135 public boolean fade() {
136 if (FloatUtils.fuzzyEquals(mOpacity, 0.0f)) {
137 return false;
138 }
139 beginTransaction(); // called on compositor thread
140 mOpacity = Math.max(mOpacity - FADE_AMOUNT, 0.0f);
141 endTransaction();
142 return true;
143 }
145 /**
146 * Restore the opacity of the scrollbar to fully opaque.
147 * Return true if the opacity was changed, or false if the scrollbars
148 * are already fully opaque.
149 */
150 public boolean unfade() {
151 if (FloatUtils.fuzzyEquals(mOpacity, 1.0f)) {
152 return false;
153 }
154 beginTransaction(); // called on compositor thread
155 mOpacity = 1.0f;
156 endTransaction();
157 return true;
158 }
160 @Override
161 public void draw(RenderContext context) {
162 if (!initialized())
163 return;
165 // Create the shader program, if necessary
166 if (mProgram == 0) {
167 createProgram();
168 }
170 // Enable the shader program
171 mRenderer.deactivateDefaultProgram();
172 activateProgram();
174 GLES20.glEnable(GLES20.GL_BLEND);
175 GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
177 if (mVertical) {
178 getVerticalRect(context, mBarRectF);
179 } else {
180 getHorizontalRect(context, mBarRectF);
181 }
182 RectUtils.round(mBarRectF, mBarRect);
184 GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
185 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, getTextureID());
187 float viewWidth = context.viewport.width();
188 float viewHeight = context.viewport.height();
190 mBarRectF.set(mBarRect.left, viewHeight - mBarRect.top, mBarRect.right, viewHeight - mBarRect.bottom);
191 mBarRectF.offset(context.offset.x, -context.offset.y);
193 // We take a 1-pixel slice from the center of the image and scale it to become the bar
194 fillRectCoordBuffer(mCoords, mBarRectF, viewWidth, viewHeight, mBodyTexCoords, mTexWidth, mTexHeight);
196 // Get the buffer and handles from the context
197 FloatBuffer coordBuffer = context.coordBuffer;
198 int positionHandle = mPositionHandle;
199 int textureHandle = mTextureHandle;
201 // Make sure we are at position zero in the buffer in case other draw methods did not
202 // clean up after themselves
203 coordBuffer.position(0);
204 coordBuffer.put(mCoords);
206 // Unbind any the current array buffer so we can use client side buffers
207 GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
209 // Vertex coordinates are x,y,z starting at position 0 into the buffer.
210 coordBuffer.position(0);
211 GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
213 // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
214 coordBuffer.position(3);
215 GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
217 GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
219 // Reset the position in the buffer for the next set of vertex and texture coordinates.
220 coordBuffer.position(0);
221 if (mVertical) {
222 // top endcap
223 mCapRectF.set(mBarRectF.left, mBarRectF.top + mCapLength, mBarRectF.right, mBarRectF.top);
224 } else {
225 // left endcap
226 mCapRectF.set(mBarRectF.left - mCapLength, mBarRectF.bottom + mBarWidth, mBarRectF.left, mBarRectF.bottom);
227 }
229 fillRectCoordBuffer(mCoords, mCapRectF, viewWidth, viewHeight, mStartCapTexCoords, mTexWidth, mTexHeight);
230 coordBuffer.put(mCoords);
232 // Vertex coordinates are x,y,z starting at position 0 into the buffer.
233 coordBuffer.position(0);
234 GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
236 // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
237 coordBuffer.position(3);
238 GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
240 GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
242 // Reset the position in the buffer for the next set of vertex and texture coordinates.
243 coordBuffer.position(0);
244 if (mVertical) {
245 // bottom endcap
246 mCapRectF.set(mBarRectF.left, mBarRectF.bottom, mBarRectF.right, mBarRectF.bottom - mCapLength);
247 } else {
248 // right endcap
249 mCapRectF.set(mBarRectF.right, mBarRectF.bottom + mBarWidth, mBarRectF.right + mCapLength, mBarRectF.bottom);
250 }
251 fillRectCoordBuffer(mCoords, mCapRectF, viewWidth, viewHeight, mEndCapTexCoords, mTexWidth, mTexHeight);
252 coordBuffer.put(mCoords);
254 // Vertex coordinates are x,y,z starting at position 0 into the buffer.
255 coordBuffer.position(0);
256 GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 20, coordBuffer);
258 // Texture coordinates are texture_x, texture_y starting at position 3 into the buffer.
259 coordBuffer.position(3);
260 GLES20.glVertexAttribPointer(textureHandle, 2, GLES20.GL_FLOAT, false, 20, coordBuffer);
262 GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
264 // Reset the position in the buffer for the next set of vertex and texture coordinates.
265 coordBuffer.position(0);
267 // Enable the default shader program again
268 deactivateProgram();
269 mRenderer.activateDefaultProgram();
270 }
272 private void getVerticalRect(RenderContext context, RectF dest) {
273 RectF viewport = context.viewport;
274 RectF pageRect = context.pageRect;
275 float viewportHeight = viewport.height() - context.offset.y;
276 float barStart = ((viewport.top - context.offset.y - pageRect.top) * (viewportHeight / pageRect.height())) + mCapLength;
277 float barEnd = ((viewport.bottom - context.offset.y - pageRect.top) * (viewportHeight / pageRect.height())) - mCapLength;
278 if (barStart > barEnd) {
279 float middle = (barStart + barEnd) / 2.0f;
280 barStart = barEnd = middle;
281 }
282 dest.set(viewport.width() - mBarWidth, barStart, viewport.width(), barEnd);
283 }
285 private void getHorizontalRect(RenderContext context, RectF dest) {
286 RectF viewport = context.viewport;
287 RectF pageRect = context.pageRect;
288 float viewportWidth = viewport.width() - context.offset.x;
289 float barStart = ((viewport.left - context.offset.x - pageRect.left) * (viewport.width() / pageRect.width())) + mCapLength;
290 float barEnd = ((viewport.right - context.offset.x - pageRect.left) * (viewport.width() / pageRect.width())) - mCapLength;
291 if (barStart > barEnd) {
292 float middle = (barStart + barEnd) / 2.0f;
293 barStart = barEnd = middle;
294 }
295 dest.set(barStart, viewport.height() - mBarWidth, barEnd, viewport.height());
296 }
297 }
