Respect FPArgs local matrix when picking a filtering mode in image shader

Includes a GM that previously drew bilerp, now draws bicubic.

Change-Id: I5e39e8adb49057b57729d9eb9748911ee8584401
Reviewed-on: https://skia-review.googlesource.com/107280
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/gm/localmatriximageshader.cpp b/gm/localmatriximageshader.cpp
index 39f5908e61..b041c70224 100644
--- a/gm/localmatriximageshader.cpp
+++ b/gm/localmatriximageshader.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "gm.h"
+#include "Resources.h"
 #include "SkCanvas.h"
 #include "SkSurface.h"
 #include "sk_tool_utils.h"
@@ -54,3 +55,15 @@ DEF_SIMPLE_GM(localmatriximageshader, canvas, 250, 250) {
     paint.setShader(image->makeShader(mode[0], mode[1], &matrix));
     canvas->drawIRect(SkIRect::MakeWH(250, 250), paint);
 }
+
+DEF_SIMPLE_GM(localmatriximageshader_filtering, canvas, 256, 256) {
+    // Test that filtering decisions (eg bicubic for upscale) are made correctly when the scale
+    // comes from a local matrix shader.
+    auto image = GetResourceAsImage("images/mandrill_256.png");
+    SkPaint p;
+    p.setFilterQuality(kHigh_SkFilterQuality);
+    SkMatrix m = SkMatrix::MakeScale(2.0f);
+    p.setShader(image->makeShader()->makeWithLocalMatrix(m));
+
+    canvas->drawRect(SkRect::MakeXYWH(0, 0, 256, 256), p);
+}