commit 2b5c7702441a5b603494d5267d3159f57c575f2a
author Brian Osman <brianosman@google.com> Wed Mar 14 10:33:56 2018 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Wed Mar 14 15:29:33 2018 +0000
tree 42ae9feea1c0fe47f3815f7f6ce2d1c12d05cf80
parent 6cecdee60988a111e8ce7ce486b734c0ecb479f7

ApproximateTransferFunction -> ApproximateCurves

Change-Id: I7afd2bcd58a5ff7a9490c37f3a2e54bbd2cbdbc5
Reviewed-on: https://skia-review.googlesource.com/114300
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

fuzz/fuzz_iccprofile_atf.c

diff --git a/fuzz/fuzz_iccprofile_atf.c b/fuzz/fuzz_iccprofile_atf.c
index 9ec7a42..c06ccb5 100644
--- a/fuzz/fuzz_iccprofile_atf.c
+++ b/fuzz/fuzz_iccprofile_atf.c
@@ -20,7 +20,7 @@
 
     skcms_TransferFunction tf;
     float max_error;
-    (void)skcms_ApproximateTransferFunction(&p, &tf, &max_error);
+    (void)skcms_ApproximateCurves(p.trc, 3, &tf, &max_error);
     (void)max_error;
 
     return 0;

iccdump.c

diff --git a/iccdump.c b/iccdump.c
index 57bb0b8..6a1a6d9 100644
--- a/iccdump.c
+++ b/iccdump.c
@@ -268,7 +268,7 @@
             svg_curves(fp, 3, profile.trc, kSVG_RGB_Colors);
             skcms_TransferFunction approx;
             float max_error;
-            if (skcms_ApproximateTransferFunction(&profile, &approx, &max_error)) {
+            if (skcms_ApproximateCurves(profile.trc, 3, &approx, &max_error)) {
                 svg_transfer_function(fp, &approx, "magenta");
             }
             svg_pop_group(fp);

skcms.h

diff --git a/skcms.h b/skcms.h
index 590b6c8..0212ed3 100644
--- a/skcms.h
+++ b/skcms.h
@@ -124,8 +124,8 @@
 // will be used.
 bool skcms_Parse(const void*, size_t, skcms_ICCProfile*);
 
-bool skcms_ApproximateTransferFunction(const skcms_ICCProfile*, skcms_TransferFunction*
-                                                              , float* max_error);
+bool skcms_ApproximateCurves(const skcms_Curve* curves, uint32_t num_curves,
+                             skcms_TransferFunction* approx, float* max_error);
 
 typedef struct {
     uint32_t       signature;

src/ICCProfile.c

diff --git a/src/ICCProfile.c b/src/ICCProfile.c
index 1077690..363f991 100644
--- a/src/ICCProfile.c
+++ b/src/ICCProfile.c
@@ -285,19 +285,21 @@
     return false;
 }
 
-bool skcms_ApproximateTransferFunction(const skcms_ICCProfile* profile,
-                                       skcms_TransferFunction* fn,
-                                       float* max_error) {
-    if (!profile || !fn) { return false; }
-
-    const skcms_Curve* curves = profile->trc;
-    if (!curves[0].table_16 || !curves[1].table_16 || !curves[2].table_16) {
+bool skcms_ApproximateCurves(const skcms_Curve* curves, uint32_t num_curves,
+                             skcms_TransferFunction* approx, float* max_error) {
+    if (!curves || !approx) {
         return false;
     }
 
-    uint64_t n = (uint64_t)curves[0].table_entries
-               + (uint64_t)curves[1].table_entries
-               + (uint64_t)curves[2].table_entries;
+    uint64_t n = 0;
+    for (uint32_t c = 0; c < num_curves; ++c) {
+        // TODO: Support approximating 8 bit curves
+        if (!curves[c].table_entries || !curves[c].table_16) {
+            return false;
+        }
+        n += (uint64_t)curves[c].table_entries;
+    }
+
     if (n > INT_MAX) {
         return false;
     }
@@ -316,7 +318,7 @@
     float* t = data + n;
 
     // Merge all channels' tables into a single array.
-    for (int c = 0; c < 3; ++c) {
+    for (uint32_t c = 0; c < num_curves; ++c) {
         for (uint32_t i = 0; i < curves[c].table_entries; ++i) {
             *x++ = i / (curves[c].table_entries - 1.0f);
             *t++ = read_big_u16(curves[c].table_16 + 2 * i) * (1 / 65535.0f);
@@ -326,7 +328,7 @@
     x = data;
     t = data + n;
 
-    bool result = skcms_TransferFunction_approximate(fn, x, t, (int)n, max_error);
+    bool result = skcms_TransferFunction_approximate(approx, x, t, (int)n, max_error);
     free(data);
     return result;
 }

test_only.c

diff --git a/test_only.c b/test_only.c
index 886b9da..e51fc4a 100644
--- a/test_only.c
+++ b/test_only.c
@@ -129,7 +129,7 @@
     float max_error;
     if (has_single_tf) {
         dump_transfer_function(fp, "TRC", &tf);
-    } else if (skcms_ApproximateTransferFunction(profile, &tf, &max_error)) {
+    } else if (skcms_ApproximateCurves(profile->trc, 3, &tf, &max_error)) {
         if (for_unit_test) {
             // The approximated transfer function can vary significantly, due to FMA, etc. In unit
             // test mode, we print at reduced precision, and omit 'd' entirely, which can vary in

tests.c

diff --git a/tests.c b/tests.c
index aada0c7..44e07d8 100644
--- a/tests.c
+++ b/tests.c
@@ -587,7 +587,7 @@
 
         skcms_TransferFunction approx_tf;
         float max_error;
-        bool approx_tf_result = skcms_ApproximateTransferFunction(&profile, &approx_tf, &max_error);
+        bool approx_tf_result = skcms_ApproximateCurves(profile.trc, 3, &approx_tf, &max_error);
         expect(approx_tf_result == !!test->expect_approx_tf);
         if (approx_tf_result) {
             // For this check, run every byte value through the forward version of one TF, and