| /* |
| * Copyright 2016 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <math.h> |
| #include <jni.h> |
| #include <android/bitmap.h> |
| |
| #include "SkCanvas.h" |
| #include "SkGraphics.h" |
| #include "SkSurface.h" |
| #include "SkString.h" |
| #include "SkTime.h" |
| |
| |
| /** |
| * Draws something into the given bitmap |
| * @param env |
| * @param thiz |
| * @param dstBitmap The bitmap to place the results of skia into |
| * @param elapsedTime The number of milliseconds since the app was started |
| */ |
| extern "C" |
| JNIEXPORT void JNICALL Java_com_example_HelloSkiaActivity_drawIntoBitmap(JNIEnv* env, |
| jobject thiz, jobject dstBitmap, jlong elapsedTime) |
| { |
| // Grab the dst bitmap info and pixels |
| AndroidBitmapInfo dstInfo; |
| void* dstPixels; |
| AndroidBitmap_getInfo(env, dstBitmap, &dstInfo); |
| AndroidBitmap_lockPixels(env, dstBitmap, &dstPixels); |
| |
| SkImageInfo info = SkImageInfo::MakeN32Premul(dstInfo.width, dstInfo.height); |
| |
| // Create a surface from the given bitmap |
| sk_sp<SkSurface> surface(SkSurface::MakeRasterDirect(info, dstPixels, dstInfo.stride)); |
| SkCanvas* canvas = surface->getCanvas(); |
| |
| // Draw something "interesting" |
| |
| // Clear the canvas with a white color |
| canvas->drawColor(SK_ColorWHITE); |
| |
| // Setup a SkPaint for drawing our text |
| SkPaint paint; |
| paint.setColor(SK_ColorBLACK); // This is a solid black color for our text |
| paint.setTextSize(SkIntToScalar(30)); // Sets the text size to 30 pixels |
| paint.setAntiAlias(true); // We turn on anti-aliasing so that the text to looks good. |
| |
| // Draw some text |
| SkString text("Skia is Best!"); |
| SkScalar fontHeight = paint.getFontSpacing(); |
| canvas->drawText(text.c_str(), text.size(), // text's data and length |
| 10, fontHeight, // X and Y coordinates to place the text |
| paint); // SkPaint to tell how to draw the text |
| |
| // Adapt the SkPaint for drawing blue lines |
| paint.setAntiAlias(false); // Turning off anti-aliasing speeds up the line drawing |
| paint.setColor(0xFF0000FF); // This is a solid blue color for our lines |
| paint.setStrokeWidth(SkIntToScalar(2)); // This makes the lines have a thickness of 2 pixels |
| |
| // Draw some interesting lines using trig functions |
| for (int i = 0; i < 100; i++) |
| { |
| float x = (float)i / 99.0f; |
| float offset = elapsedTime / 1000.0f; |
| canvas->drawLine(sin(x * M_PI + offset) * 800.0f, 0, // first endpoint |
| cos(x * M_PI + offset) * 800.0f, 800, // second endpoint |
| paint); // SkPapint to tell how to draw the line |
| } |
| |
| // Unlock the dst's pixels |
| AndroidBitmap_unlockPixels(env, dstBitmap); |
| } |