Separate image-rendering style for SVG and CSS. This fixes fuzzy pict…

…ures not only for SVG, but also for PNG, produced by Cairo/Batik.Transcoder. (#781)

plot-config-portable/src/commonMain/kotlin/jetbrains/datalore/plot/PlotSvgExportPortable.kt

@@ -19,6 +19,18 @@ object PlotSvgExportPortable {
  private val PORTABLE_SVG_STR_MAPPER =
  SvgToString(rgbEncoder = null) // data-frame --> rgb image is not supported (geom_raster)
 
+ /**
+ * @param plotSpec Raw specification of a plot or GGBunch.
+ * @param useCssPixelatedImageRendering true for CSS style "pixelated", false for SVG style "optimizeSpeed". Used for compatibility.
+ */
+ @Suppress("MemberVisibilityCanBePrivate")
+ fun buildSvgImageFromRawSpecs(
+ plotSpec: MutableMap<String, Any>,
+ useCssPixelatedImageRendering: Boolean
+ ): String {
+ return buildSvgImageFromRawSpecs(plotSpec, plotSize = null, SvgToString(rgbEncoder = null, useCssPixelatedImageRendering))
+ }
+
  /**
  * @param plotSpec Raw specification of a plot or GGBunch.
  */

plot-config-portable/src/commonTest/kotlin/plot/PlotSvgExportPortableTest.kt

@@ -22,6 +22,33 @@ internal class PlotSvgExportPortableTest {
  SvgUID.setUpForTest()
  }
 
+ @Test
+ fun fuzzyImshow() {
+ val spec = """
+ |{
+ | 'kind': 'plot',
+ | 'layers': [
+ | {
+ | 'geom': 'image',
+ | 'show_legend': true,
+ | 'href': 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAYAAACddGYaAAAAGUlEQVR4nGP4z8DwHwwZ/oOZvkDCF8jyBQCLFgnfUCS+/AAAAABJRU5ErkJggg==',
+ | 'xmin': -0.5,
+ | 'ymin': -0.5,
+ | 'xmax': 2.5,
+ | 'ymax': 1.5
+ | }
+ | ]
+ |}
+ """.trimMargin()
+
+ val svg = PlotSvgExportPortable.buildSvgImageFromRawSpecs(
+ plotSpec = parsePlotSpec(spec),
+ plotSize = DoubleVector(400.0, 300.0)
+ )
+
+ println(svg)
+ }
+
  @Test
  @Ignore
  fun svgFromSinglePlot() {

plot-config/src/jvmMain/kotlin/plot/PlotSvgExport.kt

@@ -10,18 +10,19 @@ import jetbrains.datalore.vis.svgMapper.awt.RGBEncoderAwt
 import jetbrains.datalore.vis.svgToString.SvgToString
 
 object PlotSvgExport {
- private val JVM_SVG_STR_MAPPER =
- SvgToString(RGBEncoderAwt()) // Supports data-frame --> rgb image transform (geom_raster)
-
  /**
  * @param plotSpec Raw specification of a plot or GGBunch.
  * @param plotSize Desired plot size. Has no effect on GGBunch.
+ * @param useCssPixelatedImageRendering true for CSS style "pixelated", false for SVG style "optimizeSpeed". Used for compatibility.
  */
  @Suppress("MemberVisibilityCanBePrivate")
  fun buildSvgImageFromRawSpecs(
  plotSpec: MutableMap<String, Any>,
- plotSize: DoubleVector? = null
+ plotSize: DoubleVector? = null,
+ useCssPixelatedImageRendering: Boolean = true
  ): String {
- return PlotSvgExportPortable.buildSvgImageFromRawSpecs(plotSpec, plotSize, JVM_SVG_STR_MAPPER)
+ // Supports data-frame --> rgb image transform (geom_raster)
+ val jvmSvgStrMapper = SvgToString(RGBEncoderAwt(), useCssPixelatedImageRendering)
+ return PlotSvgExportPortable.buildSvgImageFromRawSpecs(plotSpec, plotSize, jvmSvgStrMapper)
  }
 }

plot-image-export/src/jvmMain/kotlin/plot/PlotImageExport.kt

@@ -87,7 +87,7 @@ object PlotImageExport {
  }
  }
 
- val svg = buildSvgImageFromRawSpecs(plotSpec)
+ val svg = buildSvgImageFromRawSpecs(plotSpec, useCssPixelatedImageRendering = false) // Batik transcoder supports SVG style, not CSS
 
  val plotSize = fetchPlotSizeFromSvg(svg)
 

python-extension/src/nativeMain/kotlin/jetbrains/datalore/plot/pythonExtension/interop/PlotReprGenerator.kt

@@ -24,12 +24,12 @@ object PlotReprGenerator {
  }
  }
 
- fun generateSvg(plotSpecDict: CPointer<PyObject>?): CPointer<PyObject>? {
+ fun generateSvg(plotSpecDict: CPointer<PyObject>?, useCssPixelatedImageRendering: Int): CPointer<PyObject>? {
  try {
  val plotSpecMap = pyDictToMap(plotSpecDict)
 
  @Suppress("UNCHECKED_CAST")
- val svg = PlotSvgExportPortable.buildSvgImageFromRawSpecs(plotSpecMap as MutableMap<String, Any>)
+ val svg = PlotSvgExportPortable.buildSvgImageFromRawSpecs(plotSpecMap as MutableMap<String, Any>, useCssPixelatedImageRendering == 1)
  val result = Py_BuildValue("s", svg);
  return result
  } catch (e: Throwable) {

python-package/kotlin-bridge/lets_plot_kotlin_bridge.c

@@ -24,9 +24,14 @@ static PyObject* generate_html(PyObject* self, PyObject* rawPlotSpecDict) {
  return html;
 }
 
-static PyObject* export_svg(PyObject* self, PyObject* rawPlotSpecDict) {
+static PyObject* export_svg(PyObject* self, PyObject* args) {
  T_(PlotReprGenerator) reprGen = __ kotlin.root.jetbrains.datalore.plot.pythonExtension.interop.PlotReprGenerator._instance();
- PyObject* svg = __ kotlin.root.jetbrains.datalore.plot.pythonExtension.interop.PlotReprGenerator.generateSvg(reprGen, rawPlotSpecDict);
+
+ PyObject *rawPlotSpecDict;
+ int useCssPixelatedImageRendering; // 0 - false, 1 - true
+ PyArg_ParseTuple(args, "Op", &rawPlotSpecDict, &useCssPixelatedImageRendering);
+
+ PyObject* svg = __ kotlin.root.jetbrains.datalore.plot.pythonExtension.interop.PlotReprGenerator.generateSvg(reprGen, rawPlotSpecDict, useCssPixelatedImageRendering);
  return svg;
 }
 
@@ -45,7 +50,7 @@ static PyObject* export_html(PyObject* self, PyObject* args) {
 
 static PyMethodDef module_methods[] = {
  { "generate_html", (PyCFunction)generate_html, METH_O, "Generates HTML and JS sufficient for buidling of interactive plot." },
- { "export_svg", (PyCFunction)export_svg, METH_O, "Generates SVG representing plot." },
+ { "export_svg", (PyCFunction)export_svg, METH_VARARGS, "Generates SVG representing plot." },
  { "export_html", (PyCFunction)export_html, METH_VARARGS, "Generates HTML page showing plot." },
  { NULL }
 };

python-package/lets_plot/_kbridge.py

@@ -15,9 +15,9 @@ def _generate_dynamic_display_html(plot_spec: Dict) -> str:
  return lets_plot_kotlin_bridge.generate_html(plot_spec)
 
 
-def _generate_svg(plot_spec: Dict) -> str:
+def _generate_svg(plot_spec: Dict, use_css_pixelated_image_rendering: bool = True) -> str:
  plot_spec = _standardize_plot_spec(plot_spec)
- return lets_plot_kotlin_bridge.export_svg(plot_spec)
+ return lets_plot_kotlin_bridge.export_svg(plot_spec, use_css_pixelated_image_rendering)
 
 
 def _generate_static_html_page(plot_spec: Dict, iframe: bool) -> str:

python-package/lets_plot/export/simple.py

@@ -112,7 +112,8 @@ def export_png(plot: Union[PlotSpec, SupPlotsSpec, GGBunch], filename: str, scal
  return None
 
  from .. import _kbridge
- svg = _kbridge._generate_svg(plot.as_dict())
+ # Use SVG image-rendering style as Cairo doesn't support CSS image-rendering style,
+ svg = _kbridge._generate_svg(plot.as_dict(), use_css_pixelated_image_rendering=False)
 
  cairosvg.svg2png(bytestring=svg, write_to=filename, scale=scale)
 

vis-svg-portable/src/commonMain/kotlin/jetbrains/datalore/vis/svgToString/SvgToString.kt

@@ -5,17 +5,16 @@
 
 package jetbrains.datalore.vis.svgToString
 
-import jetbrains.datalore.vis.svg.SvgElement
-import jetbrains.datalore.vis.svg.SvgImageElementEx
+import jetbrains.datalore.vis.svg.*
 import jetbrains.datalore.vis.svg.SvgImageElementEx.RGBEncoder
-import jetbrains.datalore.vis.svg.SvgSvgElement
-import jetbrains.datalore.vis.svg.SvgTextNode
 import jetbrains.datalore.vis.svg.XmlNamespace.SVG_NAMESPACE_URI
 import jetbrains.datalore.vis.svg.XmlNamespace.XLINK_NAMESPACE_URI
 import jetbrains.datalore.vis.svg.XmlNamespace.XLINK_PREFIX
 
-class SvgToString(private val rgbEncoder: RGBEncoder?) {
-
+class SvgToString(
+ private val rgbEncoder: RGBEncoder?,
+ private val useCssPixelatedImageRendering: Boolean = true // true for browser, false for Batik.Transcoder or Cairo
+) {
  fun render(svg: SvgSvgElement): String {
  val buffer = StringBuilder()
  renderElement(svg, buffer, 0)
@@ -69,6 +68,15 @@ class SvgToString(private val rgbEncoder: RGBEncoder?) {
  continue
  }
  }
+
+ if (childNode is SvgImageElement) {
+ val style = when (useCssPixelatedImageRendering) {
+ true -> "image-rendering: optimizeSpeed; image-rendering: pixelated"
+ false -> "image-rendering: optimizeSpeed"
+ }
+ childNode.setAttribute(SvgConstants.SVG_STYLE_ATTRIBUTE, style)
+ }
+
  renderElement(
  childNode as SvgElement,
  buffer,