{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## geomImshow()\n",
"\n",
"`geomImshow()` displays an image specified by 2D or 3D array.\n",
"\n",
"Whether the image is grayscale or color depends on the shape of the image array:\n",
"- (M, N) - grey-scale image\n",
"- (M, N, 3) - color RGB image\n",
"- (M, N, 4) - color RGB image with alpha channel\n",
"\n",
"By default, all values in the image array will be transformed to the range [0-255] using a linear scaler."
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:14.822625Z",
"iopub.status.busy": "2025-12-03T16:04:14.821132Z",
"iopub.status.idle": "2025-12-03T16:04:16.874486Z",
"shell.execute_reply": "2025-12-03T16:04:16.874132Z"
}
},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
]
},
"metadata": {},
"output_type": "display_data"
},
{
"data": {
"text/html": [
" \n",
" "
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"%useLatestDescriptors\n",
"%use lets-plot"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:16.876892Z",
"iopub.status.busy": "2025-12-03T16:04:16.876436Z",
"iopub.status.idle": "2025-12-03T16:04:16.910760Z",
"shell.execute_reply": "2025-12-03T16:04:16.910561Z"
}
},
"outputs": [
{
"data": {
"text/plain": [
"Lets-Plot Kotlin API v.4.12.0. Frontend: Notebook with dynamically loaded JS. Lets-Plot JS v.4.8.1.\n",
"Outputs: Web (HTML+JS), Kotlin Notebook (Swing), Static SVG (hidden)"
]
},
"execution_count": 2,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"LetsPlot.getInfo()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Grayscale image\n"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:16.913216Z",
"iopub.status.busy": "2025-12-03T16:04:16.912654Z",
"iopub.status.idle": "2025-12-03T16:04:17.172398Z",
"shell.execute_reply": "2025-12-03T16:04:17.172278Z"
}
},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
]
},
"metadata": {},
"output_type": "display_data"
},
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAAAAAC4HznGAAAAEElEQVR42mNgWPWf4X8oAwAMpgL+0LIbjQAAAABJRU5ErkJggg==",
"inherit_aes": false,
"mapping": {
"paint_c": [
50.0,
200.0
]
},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": [
{
"aesthetic": "paint_c",
"end": 1.0,
"name": "",
"scale_mapper_kind": "color_grey",
"start": 0.0
}
]
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 3,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"val A2x3 = RasterData.create(\n",
" listOf(\n",
" listOf(50, 150 ,200),\n",
" listOf(200,100,50)\n",
" )\n",
")\n",
"\n",
"ggplot() + geomImshow(A2x3)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"#### Grayscale image without normalization"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:17.174441Z",
"iopub.status.busy": "2025-12-03T16:04:17.174003Z",
"iopub.status.idle": "2025-12-03T16:04:17.220664Z",
"shell.execute_reply": "2025-12-03T16:04:17.220362Z"
}
},
"outputs": [
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAAAAAC4HznGAAAAEElEQVR42mMwmnaC4USKEQAMJALvl3jyVQAAAABJRU5ErkJggg==",
"inherit_aes": false,
"mapping": {
"paint_c": [
50.0,
200.0
]
},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": [
{
"aesthetic": "paint_c",
"end": 0.7843137254901961,
"name": "",
"scale_mapper_kind": "color_grey",
"start": 0.19607843137254902
}
]
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"ggplot() + geomImshow(A2x3, norm=false)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### RGB image\n",
"\n",
"M x N x 3 array"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:17.222782Z",
"iopub.status.busy": "2025-12-03T16:04:17.222296Z",
"iopub.status.idle": "2025-12-03T16:04:17.302639Z",
"shell.execute_reply": "2025-12-03T16:04:17.302713Z"
}
},
"outputs": [
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAIAAAASFvFNAAAAEklEQVR42mP4z8DAAMVgCkgAADvYBftImLKDAAAAAElFTkSuQmCC",
"inherit_aes": false,
"mapping": {},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": []
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"val A2x3x3 = RasterData.create(\n",
" listOf(\n",
" listOf(listOf(255, 0, 0), listOf(0, 255, 0), listOf(0, 0, 255)),\n",
" listOf(listOf(0, 255, 0), listOf(0, 0, 255), listOf(255, 0, 0))\n",
" )\n",
")\n",
"\n",
"ggplot() + geomImshow(A2x3x3)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### RGB image with alpha channel\n",
"\n",
"M x N x 4 array"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:17.304943Z",
"iopub.status.busy": "2025-12-03T16:04:17.304264Z",
"iopub.status.idle": "2025-12-03T16:04:17.383245Z",
"shell.execute_reply": "2025-12-03T16:04:17.383039Z"
}
},
"outputs": [
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAYAAACddGYaAAAAGUlEQVR42mP4z8DwHwwZ/oOZvkDCF8jyBQCLFgnfxsUWGQAAAABJRU5ErkJggg==",
"inherit_aes": false,
"mapping": {},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": []
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 6,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"val A2x3x4 = RasterData.create(\n",
" listOf(\n",
" listOf(\n",
" listOf(1.0, 0.0, 0.0, 1.0), listOf(0.0, 1.0, 0.0, 1.0), listOf(0.0, 0.0, 1.0, 1.0)\n",
" ),\n",
" listOf(\n",
" listOf(0.0, 1.0, 0.0, 0.3), listOf(0.0, 0.0, 1.0, 0.3), listOf(1.0, 0.0, 0.0, 0.3)\n",
" )\n",
" )\n",
")\n",
"\n",
"ggplot() + geomImshow(A2x3x4)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Image specified by array"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Grayscale image specified by ByteArray\n"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:17.385242Z",
"iopub.status.busy": "2025-12-03T16:04:17.384942Z",
"iopub.status.idle": "2025-12-03T16:04:17.447968Z",
"shell.execute_reply": "2025-12-03T16:04:17.448090Z"
}
},
"outputs": [
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAAAAAC4HznGAAAAEElEQVR42mNgWPWf4X8oAwAMpgL+0LIbjQAAAABJRU5ErkJggg==",
"inherit_aes": false,
"mapping": {
"paint_c": [
50.0,
200.0
]
},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": [
{
"aesthetic": "paint_c",
"end": 1.0,
"name": "",
"scale_mapper_kind": "color_grey",
"start": 0.0
}
]
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 7,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"val byteArrayA2x3 = RasterData.create(\n",
" byteArrayOf(50, 150.toByte(), 200.toByte(), 200.toByte(), 100, 50),\n",
" width = 3, height = 2, nChannels = 1\n",
")\n",
"\n",
"ggplot() + geomImshow(byteArrayA2x3)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### RGB image with alpha channel specified by IntArray\n",
"Note that pixels are not packed - size of the array have to be equal to `width * height * nChannels`"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {
"execution": {
"iopub.execute_input": "2025-12-03T16:04:17.450237Z",
"iopub.status.busy": "2025-12-03T16:04:17.450028Z",
"iopub.status.idle": "2025-12-03T16:04:17.508513Z",
"shell.execute_reply": "2025-12-03T16:04:17.508258Z"
}
},
"outputs": [
{
"data": {
"application/plot+json": {
"apply_color_scheme": true,
"output": {
"kind": "plot",
"layers": [
{
"color_by": "paint_c",
"geom": "image",
"href": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAMAAAACCAYAAACddGYaAAAAGUlEQVR42mP4z8DwHwwZ/oOZAUAiAMgKAACLQwno6mpeHAAAAABJRU5ErkJggg==",
"inherit_aes": false,
"mapping": {},
"stat": "identity",
"xmax": 2.5,
"xmin": -0.5,
"ymax": 1.5,
"ymin": -0.5
}
],
"mapping": {},
"scales": []
},
"output_type": "lets_plot_spec",
"swing_enabled": true
},
"text/html": [
" \n",
" \n",
" "
]
},
"execution_count": 8,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"val intArrayA2x3x4 = RasterData.create(\n",
" listOf(\n",
" 255, 0, 0, 255, \n",
" 0, 255, 0, 255, \n",
" 0, 0, 255, 255,\n",
" 0, 255, 0, 80, \n",
" 0, 0, 255, 80, \n",
" 255, 0, 0, 80\n",
" ).toIntArray(),\n",
" width = 3, height = 2, nChannels = 4\n",
")\n",
"\n",
"ggplot() + geomImshow(intArrayA2x3x4)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Kotlin",
"language": "kotlin",
"name": "kotlin"
},
"language_info": {
"codemirror_mode": "text/x-kotlin",
"file_extension": ".kt",
"mimetype": "text/x-kotlin",
"name": "kotlin",
"nbconvert_exporter": "",
"pygments_lexer": "kotlin",
"version": "2.2.20-Beta2"
}
},
"nbformat": 4,
"nbformat_minor": 4
}