diff --git a/release/c/wuffs-unsupported-snapshot.c b/release/c/wuffs-unsupported-snapshot.c
index 145d8cd..5a649fc 100644
--- a/release/c/wuffs-unsupported-snapshot.c
+++ b/release/c/wuffs-unsupported-snapshot.c
@@ -9165,6 +9165,7 @@
 extern const char wuffs_png__error__bad_chunk[];
 extern const char wuffs_png__error__bad_filter[];
 extern const char wuffs_png__error__bad_header[];
+extern const char wuffs_png__error__bad_text_chunk_not_latin_1[];
 extern const char wuffs_png__error__missing_palette[];
 extern const char wuffs_png__error__unsupported_png_compression_method[];
 extern const char wuffs_png__error__unsupported_png_file[];
@@ -9381,6 +9382,9 @@
     uint64_t f_metadata_x;
     uint64_t f_metadata_y;
     uint64_t f_metadata_z;
+    uint32_t f_ztxt_ri;
+    uint32_t f_ztxt_wi;
+    uint64_t f_ztxt_hist_pos;
     wuffs_base__pixel_swizzler f_swizzler;
 
     wuffs_base__empty_struct (*choosy_filter_1)(
@@ -9470,7 +9474,7 @@
       uint64_t scratch;
     } s_decode_pass[1];
     struct {
-      uint8_t v_c;
+      wuffs_base__status v_zlib_status;
       uint64_t scratch;
     } s_tell_me_more[1];
   } private_data;
@@ -35327,9 +35331,11 @@
 const char wuffs_png__error__bad_chunk[] = "#png: bad chunk";
 const char wuffs_png__error__bad_filter[] = "#png: bad filter";
 const char wuffs_png__error__bad_header[] = "#png: bad header";
+const char wuffs_png__error__bad_text_chunk_not_latin_1[] = "#png: bad text chunk (not Latin-1)";
 const char wuffs_png__error__missing_palette[] = "#png: missing palette";
 const char wuffs_png__error__unsupported_png_compression_method[] = "#png: unsupported PNG compression method";
 const char wuffs_png__error__unsupported_png_file[] = "#png: unsupported PNG file";
+const char wuffs_png__error__internal_error_inconsistent_i_o[] = "#png: internal error: inconsistent I/O";
 const char wuffs_png__error__internal_error_inconsistent_chunk_type[] = "#png: internal error: inconsistent chunk type";
 const char wuffs_png__error__internal_error_inconsistent_frame_bounds[] = "#png: internal error: inconsistent frame bounds";
 const char wuffs_png__error__internal_error_inconsistent_workbuf_length[] = "#png: internal error: inconsistent workbuf length";
@@ -35375,6 +35381,42 @@
   1, 0, 3, 1, 2, 0, 4, 0,
 };
 
+static const uint16_t
+WUFFS_PNG__LATIN_1[256] WUFFS_BASE__POTENTIALLY_UNUSED = {
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  32, 33, 34, 35, 36, 37, 38, 39,
+  40, 41, 42, 43, 44, 45, 46, 47,
+  48, 49, 50, 51, 52, 53, 54, 55,
+  56, 57, 58, 59, 60, 61, 62, 63,
+  64, 65, 66, 67, 68, 69, 70, 71,
+  72, 73, 74, 75, 76, 77, 78, 79,
+  80, 81, 82, 83, 84, 85, 86, 87,
+  88, 89, 90, 91, 92, 93, 94, 95,
+  96, 97, 98, 99, 100, 101, 102, 103,
+  104, 105, 106, 107, 108, 109, 110, 111,
+  112, 113, 114, 115, 116, 117, 118, 119,
+  120, 121, 122, 123, 124, 125, 126, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 41410, 41666, 41922, 42178, 42434, 42690, 42946,
+  43202, 43458, 43714, 43970, 44226, 44482, 44738, 44994,
+  45250, 45506, 45762, 46018, 46274, 46530, 46786, 47042,
+  47298, 47554, 47810, 48066, 48322, 48578, 48834, 49090,
+  32963, 33219, 33475, 33731, 33987, 34243, 34499, 34755,
+  35011, 35267, 35523, 35779, 36035, 36291, 36547, 36803,
+  37059, 37315, 37571, 37827, 38083, 38339, 38595, 38851,
+  39107, 39363, 39619, 39875, 40131, 40387, 40643, 40899,
+  41155, 41411, 41667, 41923, 42179, 42435, 42691, 42947,
+  43203, 43459, 43715, 43971, 44227, 44483, 44739, 44995,
+  45251, 45507, 45763, 46019, 46275, 46531, 46787, 47043,
+  47299, 47555, 47811, 48067, 48323, 48579, 48835, 49091,
+};
+
 // ---------------- Private Initializer Prototypes
 
 // ---------------- Private Function Prototypes
@@ -40455,6 +40497,15 @@
   wuffs_base__status status = wuffs_base__make_status(NULL);
 
   uint8_t v_c = 0;
+  uint16_t v_c2 = 0;
+  wuffs_base__io_buffer u_w = wuffs_base__empty_io_buffer();
+  wuffs_base__io_buffer* v_w = &u_w;
+  uint8_t* iop_v_w WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
+  uint8_t* io0_v_w WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
+  uint8_t* io1_v_w WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
+  uint8_t* io2_v_w WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
+  uint64_t v_num_written = 0;
+  uint64_t v_w_mark = 0;
   uint64_t v_r_mark = 0;
   wuffs_base__status v_zlib_status = wuffs_base__make_status(NULL);
 
@@ -40484,7 +40535,7 @@
 
   uint32_t coro_susp_point = self->private_impl.p_tell_me_more[0];
   if (coro_susp_point) {
-    v_c = self->private_data.s_tell_me_more[0].v_c;
+    v_zlib_status = self->private_data.s_tell_me_more[0].v_zlib_status;
   }
   switch (coro_susp_point) {
     WUFFS_BASE__COROUTINE_SUSPENSION_POINT_0;
@@ -40506,6 +40557,7 @@
         }
       }
       self->private_impl.f_zlib_is_dirty = true;
+      self->private_impl.f_ztxt_hist_pos = 0;
     }
     label__loop__continue:;
     while (true) {
@@ -40614,34 +40666,86 @@
           status = v_zlib_status;
           WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(2);
         } else if (self->private_impl.f_chunk_type == 1951945850) {
-          {
-            const uint8_t *o_2_io2_a_src = io2_a_src;
-            wuffs_base__io_reader__limit(&io2_a_src, iop_a_src,
-                ((uint64_t)(self->private_impl.f_chunk_length)));
-            if (a_src) {
-              a_src->meta.wi = ((size_t)(io2_a_src - a_src->data.ptr));
-            }
-            v_r_mark = ((uint64_t)(iop_a_src - io0_a_src));
+          if (self->private_impl.f_ztxt_ri == self->private_impl.f_ztxt_wi) {
             {
-              if (a_dst) {
-                a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
+              wuffs_base__io_buffer* o_2_v_w = v_w;
+              uint8_t *o_2_iop_v_w = iop_v_w;
+              uint8_t *o_2_io0_v_w = io0_v_w;
+              uint8_t *o_2_io1_v_w = io1_v_w;
+              uint8_t *o_2_io2_v_w = io2_v_w;
+              v_w = wuffs_base__io_writer__set(
+                  &u_w,
+                  &iop_v_w,
+                  &io0_v_w,
+                  &io1_v_w,
+                  &io2_v_w,
+                  wuffs_base__make_slice_u8(self->private_data.f_dst_palette, 1024),
+                  self->private_impl.f_ztxt_hist_pos);
+              {
+                const uint8_t *o_3_io2_a_src = io2_a_src;
+                wuffs_base__io_reader__limit(&io2_a_src, iop_a_src,
+                    ((uint64_t)(self->private_impl.f_chunk_length)));
+                if (a_src) {
+                  a_src->meta.wi = ((size_t)(io2_a_src - a_src->data.ptr));
+                }
+                v_w_mark = ((uint64_t)(iop_v_w - io0_v_w));
+                v_r_mark = ((uint64_t)(iop_a_src - io0_a_src));
+                {
+                  u_w.meta.wi = ((size_t)(iop_v_w - u_w.data.ptr));
+                  if (a_src) {
+                    a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
+                  }
+                  wuffs_base__status t_2 = wuffs_zlib__decoder__transform_io(&self->private_data.f_zlib, v_w, a_src, wuffs_base__utility__empty_slice_u8());
+                  v_zlib_status = t_2;
+                  iop_v_w = u_w.data.ptr + u_w.meta.wi;
+                  if (a_src) {
+                    iop_a_src = a_src->data.ptr + a_src->meta.ri;
+                  }
+                }
+                wuffs_base__u32__sat_sub_indirect(&self->private_impl.f_chunk_length, ((uint32_t)((wuffs_base__io__count_since(v_r_mark, ((uint64_t)(iop_a_src - io0_a_src))) & 4294967295))));
+                v_num_written = wuffs_base__io__count_since(v_w_mark, ((uint64_t)(iop_v_w - io0_v_w)));
+                io2_a_src = o_3_io2_a_src;
+                if (a_src) {
+                  a_src->meta.wi = ((size_t)(io2_a_src - a_src->data.ptr));
+                }
               }
-              if (a_src) {
-                a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
-              }
-              wuffs_base__status t_2 = wuffs_zlib__decoder__transform_io(&self->private_data.f_zlib, a_dst, a_src, wuffs_base__utility__empty_slice_u8());
-              v_zlib_status = t_2;
-              if (a_dst) {
-                iop_a_dst = a_dst->data.ptr + a_dst->meta.wi;
-              }
-              if (a_src) {
-                iop_a_src = a_src->data.ptr + a_src->meta.ri;
-              }
+              v_w = o_2_v_w;
+              iop_v_w = o_2_iop_v_w;
+              io0_v_w = o_2_io0_v_w;
+              io1_v_w = o_2_io1_v_w;
+              io2_v_w = o_2_io2_v_w;
             }
-            wuffs_base__u32__sat_sub_indirect(&self->private_impl.f_chunk_length, ((uint32_t)((wuffs_base__io__count_since(v_r_mark, ((uint64_t)(iop_a_src - io0_a_src))) & 4294967295))));
-            io2_a_src = o_2_io2_a_src;
-            if (a_src) {
-              a_src->meta.wi = ((size_t)(io2_a_src - a_src->data.ptr));
+            if (v_num_written > 1024) {
+              status = wuffs_base__make_status(wuffs_png__error__internal_error_inconsistent_i_o);
+              goto exit;
+            }
+            self->private_impl.f_ztxt_ri = 0;
+            self->private_impl.f_ztxt_wi = ((uint32_t)(v_num_written));
+            wuffs_base__u64__sat_add_indirect(&self->private_impl.f_ztxt_hist_pos, v_num_written);
+          }
+          while (self->private_impl.f_ztxt_ri < self->private_impl.f_ztxt_wi) {
+            v_c2 = WUFFS_PNG__LATIN_1[self->private_data.f_dst_palette[self->private_impl.f_ztxt_ri]];
+            if (v_c2 == 0) {
+              status = wuffs_base__make_status(wuffs_png__error__bad_text_chunk_not_latin_1);
+              goto exit;
+            } else if (v_c2 <= 127) {
+              if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 0) {
+                status = wuffs_base__make_status(wuffs_base__suspension__short_write);
+                WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(3);
+                v_c2 = 0;
+                goto label__loop__continue;
+              }
+              self->private_impl.f_ztxt_ri += 1;
+              (wuffs_base__poke_u8be__no_bounds_check(iop_a_dst, ((uint8_t)(v_c2))), iop_a_dst += 1);
+            } else {
+              if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 1) {
+                status = wuffs_base__make_status(wuffs_base__suspension__short_write);
+                WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(4);
+                v_c2 = 0;
+                goto label__loop__continue;
+              }
+              self->private_impl.f_ztxt_ri += 1;
+              (wuffs_base__poke_u16le__no_bounds_check(iop_a_dst, v_c2), iop_a_dst += 2);
             }
           }
           if (wuffs_base__status__is_ok(&v_zlib_status)) {
@@ -40656,13 +40760,32 @@
               goto exit;
             }
             goto ok;
+          } else if (v_zlib_status.repr != wuffs_base__suspension__short_write) {
+            status = v_zlib_status;
+            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(5);
           }
-          status = v_zlib_status;
-          WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(3);
         } else {
           status = wuffs_base__make_status(wuffs_png__error__internal_error_inconsistent_chunk_type);
           goto exit;
         }
+      } else if ((self->private_impl.f_chunk_type == 1951945833) && (self->private_impl.f_metadata_fourcc == 1263947862)) {
+        while (true) {
+          if (self->private_impl.f_chunk_length <= 0) {
+            goto label__loop__break;
+          } else if (((uint64_t)(io2_a_src - iop_a_src)) <= 0) {
+            status = wuffs_base__make_status(wuffs_base__suspension__short_read);
+            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(6);
+            goto label__loop__continue;
+          } else if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 0) {
+            status = wuffs_base__make_status(wuffs_base__suspension__short_write);
+            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(7);
+            goto label__loop__continue;
+          }
+          self->private_impl.f_chunk_length -= 1;
+          v_c = wuffs_base__peek_u8be__no_bounds_check(iop_a_src);
+          iop_a_src += 1;
+          (wuffs_base__poke_u8be__no_bounds_check(iop_a_dst, v_c), iop_a_dst += 1);
+        }
       } else {
         while (true) {
           if (self->private_impl.f_chunk_length <= 0) {
@@ -40673,7 +40796,7 @@
             goto label__loop__break;
           } else if (((uint64_t)(io2_a_src - iop_a_src)) <= 0) {
             status = wuffs_base__make_status(wuffs_base__suspension__short_read);
-            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(4);
+            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(8);
             goto label__loop__continue;
           }
           v_c = wuffs_base__peek_u8be__no_bounds_check(iop_a_src);
@@ -40682,14 +40805,31 @@
             iop_a_src += 1;
             goto label__loop__break;
           }
-          if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 0) {
-            status = wuffs_base__make_status(wuffs_base__suspension__short_write);
-            WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(5);
-            goto label__loop__continue;
+          v_c2 = WUFFS_PNG__LATIN_1[v_c];
+          if (v_c2 == 0) {
+            status = wuffs_base__make_status(wuffs_png__error__bad_text_chunk_not_latin_1);
+            goto exit;
+          } else if (v_c2 <= 127) {
+            if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 0) {
+              status = wuffs_base__make_status(wuffs_base__suspension__short_write);
+              WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(9);
+              v_c2 = 0;
+              goto label__loop__continue;
+            }
+            self->private_impl.f_chunk_length -= 1;
+            iop_a_src += 1;
+            (wuffs_base__poke_u8be__no_bounds_check(iop_a_dst, ((uint8_t)(v_c2))), iop_a_dst += 1);
+          } else {
+            if (((uint64_t)(io2_a_dst - iop_a_dst)) <= 1) {
+              status = wuffs_base__make_status(wuffs_base__suspension__short_write);
+              WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(10);
+              v_c2 = 0;
+              goto label__loop__continue;
+            }
+            self->private_impl.f_chunk_length -= 1;
+            iop_a_src += 1;
+            (wuffs_base__poke_u16le__no_bounds_check(iop_a_dst, v_c2), iop_a_dst += 2);
           }
-          self->private_impl.f_chunk_length -= 1;
-          iop_a_src += 1;
-          (wuffs_base__poke_u8be__no_bounds_check(iop_a_dst, v_c), iop_a_dst += 1);
         }
       }
     }
@@ -40703,7 +40843,7 @@
         }
         self->private_impl.f_chunk_length -= 2;
         {
-          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(6);
+          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(11);
           if (WUFFS_BASE__UNLIKELY(iop_a_src == io2_a_src)) {
             status = wuffs_base__make_status(wuffs_base__suspension__short_read);
             goto suspend;
@@ -40720,7 +40860,7 @@
           goto exit;
         }
         {
-          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(7);
+          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(12);
           if (WUFFS_BASE__UNLIKELY(iop_a_src == io2_a_src)) {
             status = wuffs_base__make_status(wuffs_base__suspension__short_read);
             goto suspend;
@@ -40742,7 +40882,7 @@
             }
             self->private_impl.f_chunk_length -= 1;
             {
-              WUFFS_BASE__COROUTINE_SUSPENSION_POINT(8);
+              WUFFS_BASE__COROUTINE_SUSPENSION_POINT(13);
               if (WUFFS_BASE__UNLIKELY(iop_a_src == io2_a_src)) {
                 status = wuffs_base__make_status(wuffs_base__suspension__short_read);
                 goto suspend;
@@ -40763,7 +40903,7 @@
         }
         self->private_impl.f_chunk_length -= 1;
         {
-          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(9);
+          WUFFS_BASE__COROUTINE_SUSPENSION_POINT(14);
           if (WUFFS_BASE__UNLIKELY(iop_a_src == io2_a_src)) {
             status = wuffs_base__make_status(wuffs_base__suspension__short_read);
             goto suspend;
@@ -40783,7 +40923,7 @@
         goto exit;
       }
       self->private_data.s_tell_me_more[0].scratch = 4;
-      WUFFS_BASE__COROUTINE_SUSPENSION_POINT(10);
+      WUFFS_BASE__COROUTINE_SUSPENSION_POINT(15);
       if (self->private_data.s_tell_me_more[0].scratch > ((uint64_t)(io2_a_src - iop_a_src))) {
         self->private_data.s_tell_me_more[0].scratch -= ((uint64_t)(io2_a_src - iop_a_src));
         iop_a_src = io2_a_src;
@@ -40810,7 +40950,7 @@
   suspend:
   self->private_impl.p_tell_me_more[0] = wuffs_base__status__is_suspension(&status) ? coro_susp_point : 0;
   self->private_impl.active_coroutine = wuffs_base__status__is_suspension(&status) ? 4 : 0;
-  self->private_data.s_tell_me_more[0].v_c = v_c;
+  self->private_data.s_tell_me_more[0].v_zlib_status = v_zlib_status;
 
   goto exit;
   exit:
diff --git a/script/print-png-latin-1.go b/script/print-png-latin-1.go
new file mode 100644
index 0000000..34fc86f
--- /dev/null
+++ b/script/print-png-latin-1.go
@@ -0,0 +1,57 @@
+// Copyright 2021 The Wuffs Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build ignore
+// +build ignore
+
+package main
+
+// print-png-latin-1.go prints the UTF-8 encoding of the std/png Latin-1 table.
+//
+// Usage: go run print-png-latin-1.go
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	if err := main1(); err != nil {
+		os.Stderr.WriteString(err.Error() + "\n")
+		os.Exit(1)
+	}
+}
+
+func main1() error {
+	// The PNG spec (https://www.w3.org/TR/PNG/) says "*printable* [emphasis
+	// added] Latin-1 characters and spaces (only character codes 32-126 and
+	// 161-255 decimal are allowed)".
+	//
+	// See also https://www.w3.org/TR/2003/REC-PNG-20031110/iso_8859-1.txt
+	for r := rune(0); r <= 0xFF; r++ {
+		if (r < 32) || ((126 < r) && (r < 161)) {
+			fmt.Printf(" 0x0000,")
+		} else if r < 128 {
+			fmt.Printf(" 0x%04X,", r)
+		} else {
+			s := fmt.Sprintf("%c", r)
+			fmt.Printf(" 0x%02X%02X,", s[1], s[0]) // UTF-8 as little-endian uint16.
+		}
+
+		if r%8 == 7 {
+			fmt.Println()
+		}
+	}
+	return nil
+}
diff --git a/std/png/common_consts.wuffs b/std/png/common_consts.wuffs
index d85a6d8..2c4e419 100644
--- a/std/png/common_consts.wuffs
+++ b/std/png/common_consts.wuffs
@@ -17,10 +17,12 @@
 pub status "#bad chunk"
 pub status "#bad filter"
 pub status "#bad header"
+pub status "#bad text chunk (not Latin-1)"
 pub status "#missing palette"
 pub status "#unsupported PNG compression method"
 pub status "#unsupported PNG file"
 
+pri status "#internal error: inconsistent I/O"
 pri status "#internal error: inconsistent chunk type"
 pri status "#internal error: inconsistent frame bounds"
 pri status "#internal error: inconsistent workbuf length"
@@ -101,3 +103,40 @@
 	4,  // color_type == 6: RGBA
 	0,
 ]
+
+// LATIN_1 converts from printable Latin-1 (ISO/IEC 8859-1) to UTF-8 (encoded
+// as little-endian u16). It was created by script/print-png-latin-1.go.
+pri const LATIN_1 : array[256] base.u16 = [
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
+	0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,
+	0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
+	0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,
+	0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
+	0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,
+	0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
+	0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,
+	0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
+	0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F,
+	0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
+	0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0xA1C2, 0xA2C2, 0xA3C2, 0xA4C2, 0xA5C2, 0xA6C2, 0xA7C2,
+	0xA8C2, 0xA9C2, 0xAAC2, 0xABC2, 0xACC2, 0xADC2, 0xAEC2, 0xAFC2,
+	0xB0C2, 0xB1C2, 0xB2C2, 0xB3C2, 0xB4C2, 0xB5C2, 0xB6C2, 0xB7C2,
+	0xB8C2, 0xB9C2, 0xBAC2, 0xBBC2, 0xBCC2, 0xBDC2, 0xBEC2, 0xBFC2,
+	0x80C3, 0x81C3, 0x82C3, 0x83C3, 0x84C3, 0x85C3, 0x86C3, 0x87C3,
+	0x88C3, 0x89C3, 0x8AC3, 0x8BC3, 0x8CC3, 0x8DC3, 0x8EC3, 0x8FC3,
+	0x90C3, 0x91C3, 0x92C3, 0x93C3, 0x94C3, 0x95C3, 0x96C3, 0x97C3,
+	0x98C3, 0x99C3, 0x9AC3, 0x9BC3, 0x9CC3, 0x9DC3, 0x9EC3, 0x9FC3,
+	0xA0C3, 0xA1C3, 0xA2C3, 0xA3C3, 0xA4C3, 0xA5C3, 0xA6C3, 0xA7C3,
+	0xA8C3, 0xA9C3, 0xAAC3, 0xABC3, 0xACC3, 0xADC3, 0xAEC3, 0xAFC3,
+	0xB0C3, 0xB1C3, 0xB2C3, 0xB3C3, 0xB4C3, 0xB5C3, 0xB6C3, 0xB7C3,
+	0xB8C3, 0xB9C3, 0xBAC3, 0xBBC3, 0xBCC3, 0xBDC3, 0xBEC3, 0xBFC3,
+]
diff --git a/std/png/decode_png.wuffs b/std/png/decode_png.wuffs
index f3a37dd..54e17e7 100644
--- a/std/png/decode_png.wuffs
+++ b/std/png/decode_png.wuffs
@@ -166,12 +166,25 @@
 	metadata_y      : base.u64,
 	metadata_z      : base.u64,
 
+	// ztxt_ri and ztxt_wi are read and write indexes into the dst_palette
+	// buffer, re-purposed as a zlib uncompression buffer for zTXt chunks. The
+	// upper bound, 1024, is the same as the dst_palette length.
+	ztxt_ri : base.u32[..= 1024],
+	ztxt_wi : base.u32[..= 1024],
+	// ztxt_hist_pos is the history position: how many uncompressed bytes have
+	// been generated.
+	ztxt_hist_pos : base.u64,
+
 	swizzler : base.pixel_swizzler,
 	util     : base.utility,
 )(
 	crc32 : crc32.ieee_hasher,
 	zlib  : zlib.decoder,
 
+	// dst_palette and src_palette are used by the swizzler, during
+	// decode_frame. src_palette is initialized by processing the PLTE chunk.
+	// dst_palette is also re-purposed as a zlib uncompression buffer for zTXt
+	// chunks, during decode_image_config.
 	dst_palette : array[4 * 256] base.u8,
 	src_palette : array[4 * 256] base.u8,
 )
@@ -1324,6 +1337,10 @@
 
 pub func decoder.tell_me_more?(dst: base.io_writer, minfo: nptr base.more_information, src: base.io_reader) {
 	var c           : base.u8
+	var c2          : base.u16
+	var w           : base.io_writer
+	var num_written : base.u64
+	var w_mark      : base.u64
 	var r_mark      : base.u64
 	var zlib_status : base.status
 
@@ -1342,6 +1359,7 @@
 			}
 		}
 		this.zlib_is_dirty = true
+		this.ztxt_hist_pos = 0
 	}
 
 	while.loop true {
@@ -1395,28 +1413,87 @@
 				yield? zlib_status
 
 			} else if this.chunk_type == 'zTXt'le {
-				// TODO: Convert uncompressed data from Latin-1 to UTF-8.
-				io_limit (io: args.src, limit: this.chunk_length as base.u64) {
-					r_mark = args.src.mark()
-					zlib_status =? this.zlib.transform_io?(
-						dst: args.dst, src: args.src, workbuf: this.util.empty_slice_u8())
-					this.chunk_length ~sat-=
-						(args.src.count_since(mark: r_mark) & 0xFFFF_FFFF) as base.u32
+				// Fill this.dst_palette, zlib-uncompressing producing Latin-1.
+				if this.ztxt_ri == this.ztxt_wi {
+					io_bind (io: w, data: this.dst_palette[..], history_position: this.ztxt_hist_pos) {
+						io_limit (io: args.src, limit: this.chunk_length as base.u64) {
+							w_mark = w.mark()
+							r_mark = args.src.mark()
+							zlib_status =? this.zlib.transform_io?(
+								dst: w, src: args.src, workbuf: this.util.empty_slice_u8())
+							this.chunk_length ~sat-=
+								(args.src.count_since(mark: r_mark) & 0xFFFF_FFFF) as base.u32
+							num_written = w.count_since(mark: w_mark)
+						}
+					}
+					if num_written > 1024 {
+						return "#internal error: inconsistent I/O"
+					}
+					this.ztxt_ri = 0
+					this.ztxt_wi = num_written as base.u32
+					this.ztxt_hist_pos ~sat+= num_written
 				}
 
+				// Drain this.dst_palette, converting from Latin-1 to UTF-8.
+				while this.ztxt_ri < this.ztxt_wi {
+					assert this.ztxt_ri < 1024 via "a < b: a < c; c <= b"(c: this.ztxt_wi)
+					c2 = LATIN_1[this.dst_palette[this.ztxt_ri]]
+					if c2 == 0 {
+						return "#bad text chunk (not Latin-1)"
+					} else if c2 <= 0x7F {
+						if args.dst.length() <= 0 {
+							yield? base."$short write"
+							c2 = 0
+							continue.loop
+						}
+						this.ztxt_ri += 1
+						args.dst.write_u8_fast!(a: c2 as base.u8)
+					} else {
+						if args.dst.length() <= 1 {
+							yield? base."$short write"
+							c2 = 0
+							continue.loop
+						}
+						this.ztxt_ri += 1
+						args.dst.write_u16le_fast!(a: c2)
+					}
+				} endwhile
+
 				if zlib_status.is_ok() {
 					this.metadata_is_zlib_compressed = false
 					break.loop
 				} else if not zlib_status.is_suspension() {
 					return zlib_status
+				} else if zlib_status <> base."$short write" {
+					yield? zlib_status
 				}
-				yield? zlib_status
 
 			} else {
 				return "#internal error: inconsistent chunk type"
 			}
 
+		} else if (this.chunk_type == 'iTXt'le) and (this.metadata_fourcc == 'KVPV'be) {
+			// iTXt value is UTF-8.
+			//
+			// TODO: verify data is UTF-8.
+			while true {
+				if this.chunk_length <= 0 {
+					break.loop
+				} else if args.src.length() <= 0 {
+					yield? base."$short read"
+					continue.loop
+				} else if args.dst.length() <= 0 {
+					yield? base."$short write"
+					continue.loop
+				}
+				this.chunk_length -= 1
+				c = args.src.peek_u8()
+				args.src.skip_u32_fast!(actual: 1, worst_case: 1)
+				args.dst.write_u8_fast!(a: c)
+			} endwhile
+
 		} else {
+			// Other uncompressed keys and values are Latin-1.
 			while true {
 				if this.chunk_length <= 0 {
 					// Keys are NUL-terminated but values are not.
@@ -1434,14 +1511,28 @@
 					args.src.skip_u32_fast!(actual: 1, worst_case: 1)
 					break.loop
 				}
-				// TODO: Convert from Latin-1 to UTF-8.
-				if args.dst.length() <= 0 {
-					yield? base."$short write"
-					continue.loop
+				c2 = LATIN_1[c]
+				if c2 == 0 {
+					return "#bad text chunk (not Latin-1)"
+				} else if c2 <= 0x7F {
+					if args.dst.length() <= 0 {
+						yield? base."$short write"
+						c2 = 0
+						continue.loop
+					}
+					this.chunk_length -= 1
+					args.src.skip_u32_fast!(actual: 1, worst_case: 1)
+					args.dst.write_u8_fast!(a: c2 as base.u8)
+				} else {
+					if args.dst.length() <= 1 {
+						yield? base."$short write"
+						c2 = 0
+						continue.loop
+					}
+					this.chunk_length -= 1
+					args.src.skip_u32_fast!(actual: 1, worst_case: 1)
+					args.dst.write_u16le_fast!(a: c2)
 				}
-				this.chunk_length -= 1
-				args.src.skip_u32_fast!(actual: 1, worst_case: 1)
-				args.dst.write_u8_fast!(a: c)
 			} endwhile
 		}
 	} endwhile.loop
diff --git a/test/c/std/png.c b/test/c/std/png.c
index c291fee..102e3eb 100644
--- a/test/c/std/png.c
+++ b/test/c/std/png.c
@@ -735,17 +735,16 @@
   CHECK_STRING(read_file(&src, "test/data/artificial-png/key-value-pairs.png"));
 
   const char* wants[] = {
-      // TODO: the callee should produce UTF-8, not Latin-1.
-      "Key",             //
-      "English",         //
-      "Cl\xE9",          //
-      "Fran\xE7\x61is",  //
-      "zl\xEF\x62K",     //
-      "zl\xEF\x62V",     //
-      "U-Key",           //
-      "U-значение",      //
-      "Z-K\xEBy",        //
-      "Z-значение",      //
+      "Key",         //
+      "English",     //
+      "Clé",         //
+      "Français",    //
+      "zlïbK",       //
+      "zlïbV",       //
+      "U-Key",       //
+      "U-значение",  //
+      "Z-Këy",       //
+      "Z-значение",  //
   };
 
   wuffs_png__decoder dec;