Sketch DM refactor.

dm/DMImageTask.cpp

-#include "DMImageTask.h"
-#include "DMUtil.h"
-#include "DMWriteTask.h"
-#include "SkImageDecoder.h"
-#include "SkRandom.h"
-
-#include <string.h>
-
-namespace DM {
-
-// This converts file names like "mandrill_128.r11.ktx" into
-// "mandrill-128-r11_ktx" or "mandrill-128-r11-5-subsets_ktx".
-static SkString task_name(SkString filename, int subsets) {
-    const char* ext = strrchr(filename.c_str(), '.');
-    SkString name(filename.c_str(), ext - filename.c_str());
-    if (subsets > 0) {
-        name.appendf("_%d_subsets", subsets);
-    }
-    name = FileToTaskName(name);  // Promote any stray '.' in the filename to '_'.
-    name.append(ext);             // Tack on the extension, including the '.'.
-    return FileToTaskName(name);  // Promote that last '.' to '_', other '_' to '-'.
-}
-
-ImageTask::ImageTask(Reporter* r, TaskRunner* t, const SkData* encoded, SkString name, int subsets)
-    : CpuTask(r, t)
-    , fEncoded(SkRef(encoded))
-    , fName(task_name(name, subsets))
-    , fSubsets(subsets) {}
-
-void ImageTask::draw() {
-    if (fSubsets == 0) {
-        // Decoding the whole image is considerably simpler than decoding subsets!
-        SkBitmap bitmap;
-        if (!SkImageDecoder::DecodeMemory(fEncoded->data(), fEncoded->size(), &bitmap)) {
-            return this->fail("Can't DecodeMemory");
-        }
-        this->spawnChild(SkNEW_ARGS(WriteTask, (*this, "image", bitmap)));
-        return;
-    }
-
-    SkMemoryStream stream(fEncoded->data(), fEncoded->size());
-    SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
-    if (!decoder) {
-        return this->fail("Can't find good decoder.");
-    }
-
-    int w,h;
-    if (!decoder->buildTileIndex(&stream, &w, &h) || w*h == 1) {
-        return;  // Subset decoding is not always supported.
-    }
-
-    SkBitmap composite;
-    composite.allocN32Pixels(w,h);  // We're lazy here and just always use native 8888.
-    composite.eraseColor(SK_ColorTRANSPARENT);
-    SkCanvas canvas(composite);
-
-    SkRandom rand;
-    for (int i = 0; i < fSubsets; i++) {
-        SkIRect rect;
-        do {
-            rect.fLeft   = rand.nextULessThan(w);
-            rect.fTop    = rand.nextULessThan(h);
-            rect.fRight  = rand.nextULessThan(w);
-            rect.fBottom = rand.nextULessThan(h);
-            rect.sort();
-        } while (rect.isEmpty());
-
-        SkBitmap subset;
-        if (!decoder->decodeSubset(&subset, rect, kN32_SkColorType)) {
-            return this->fail("Could not decode subset.");
-        }
-        canvas.drawBitmap(subset, SkIntToScalar(rect.fLeft), SkIntToScalar(rect.fTop));
-    }
-    canvas.flush();
-    this->spawnChild(SkNEW_ARGS(WriteTask, (*this, "image", composite)));
-}
-
-}  // namespace DM