{
"cells": [
{
"cell_type": "markdown",
"id": "issue-706-title",
"metadata": {},
"source": [
"# Issue #706, \"scale_alpha: conflict of constant and mapped values of alpha aesthetic\"\n",
"\n",
"When a layer uses a constant numeric aesthetic (e.g. `geom_point(alpha=0.5)`) alongside another layer\n",
"that maps the same aesthetic to data with a non-identity transform (e.g. `scale_alpha(trans='log10')`),\n",
"the constant was incorrectly run through the transform, producing a wrong value. For alpha this often meant\n",
"a negative value that was later clamped to 0."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "issue-706-setup",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
"\n",
" \n",
" \n",
" "
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"from lets_plot import *\n",
"\n",
"LetsPlot.setup_html()\n",
"\n",
"data = {\n",
" 'x': [-3, -2, -1, 0, 1, 2, 3],\n",
" 'y': [-3, -2, -1, 0, 1, 2, 3],\n",
" # negative and zero values are outside log10 domain; only 1, 4, 9 survive\n",
" 'v': [-9, -4, -1, 0, 1, 4, 9],\n",
"}"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-1",
"metadata": {},
"source": [
"## 1. Original failing case: constant `alpha=0.5` + `scale_alpha(trans='log10')`\n",
"\n",
"Before the fix the large red points (Layer 1) were invisible (alpha clamped to 0).\n",
"After the fix they should appear at 50% opacity.\n",
"\n",
"ggplot2 behavior: produces a warning about out-of-domain values but renders both layers."
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "issue-706-case1",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 2,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=0.5, color='red') # constant alpha - must stay 0.5\n",
" + geom_point(aes(alpha='v'), color='black') # mapped alpha through log10\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Original case: constant alpha=0.5 + log10 transform')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-2",
"metadata": {},
"source": [
"## 2. `trans='sqrt'` - wrong value before, correct after\n",
"\n",
"With `sqrt`, `sqrt(0.5) ~= 0.707` fell inside [0,1] so points were visible but at the wrong\n",
"opacity. After the fix the large red points must appear at exactly 50% opacity.\n"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "issue-706-case2",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 3,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=0.5, color='red')\n",
" + geom_point(aes(alpha='v'), color='black')\n",
" + scale_alpha(trans='sqrt')\n",
" + ggtitle('Constant alpha=0.5 + sqrt transform (was ~0.71 before fix)')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-3",
"metadata": {},
"source": [
"## 3. `trans='reverse'` - negated constant before, correct after\n",
"\n",
"The `reverse` transform maps `v` to `-v`. With the old code the constant 0.5 became -0.5\n",
"(clamped to 0). After the fix it stays 0.5.\n"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "issue-706-case3",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"data_pos = {\n",
" 'x': [1, 2, 3, 4, 5],\n",
" 'y': [1, 2, 3, 4, 5],\n",
" 'v': [0.1, 0.3, 0.5, 0.7, 0.9],\n",
"}\n",
"\n",
"(\n",
" ggplot(data_pos, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=0.5, color='red')\n",
" + geom_point(aes(alpha='v'), color='black')\n",
" + scale_alpha(trans='reverse')\n",
" + ggtitle('Constant alpha=0.5 + reverse transform')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-4",
"metadata": {},
"source": [
"## 4. Regression: constant alpha, no scale transform\n",
"\n",
"Without a transform the constant must pass through unchanged. Both layers visible."
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "issue-706-case4",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=0.5, color='red') # constant - must remain 0.5\n",
" + geom_point(aes(alpha='v'), color='black') # mapped, identity transform\n",
" + scale_alpha()\n",
" + ggtitle('Regression: constant alpha + identity transform (no change expected)')\n",
")\n"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-5",
"metadata": {},
"source": [
"## 5. Regression: mapped alpha with `log10`, no constant layer\n",
"\n",
"This worked before and must continue to work. Only positive `v` values (1, 4, 9) are mapped;\n",
"the rest render with the NA alpha."
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "issue-706-case5",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 6,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(aes(alpha='v'), color='red', size=8)\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Regression: only mapped alpha + log10 (no constant layer)')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-6",
"metadata": {},
"source": [
"## 6. Positional constant on a log10 x-scale (must still be transformed)\n",
"\n",
"Unlike non-positional constants, a positional constant such as `xintercept=10` on a log10\n",
"x-axis must be transformed (so it appears at the correct position on the log scale).\n",
"Verify `geom_vline(xintercept=10)` appears at x=10 on the log10 x-axis."
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "issue-706-case6",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 7,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"data_pos2 = {'x': [1, 2, 5, 10, 50, 100], 'y': [1, 2, 3, 4, 5, 6]}\n",
"\n",
"(\n",
" ggplot(data_pos2, aes('x', 'y'))\n",
" + geom_point(size=4)\n",
" + geom_vline(xintercept=10, color='red', linetype='dashed') # must align with x=10 points\n",
" + scale_x_log10()\n",
" + ggtitle('Positional constant (xintercept=10) on log10 x-axis - must stay at x=10')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-7",
"metadata": {},
"source": [
"## 7. Two mapped layers sharing `scale_alpha(trans='log10')`\n",
"\n",
"Both layers use `aes(alpha=...)`. Neither has a constant. Both must render correctly."
]
},
{
"cell_type": "code",
"execution_count": 8,
"id": "issue-706-case7",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 8,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"import numpy as np\n",
"\n",
"data_a = {'x': [1, 2, 3, 4, 5], 'y': [2, 2, 2, 2, 2], 'v': [1, 2, 3, 4, 5]}\n",
"data_b = {'x': [1, 2, 3, 4, 5], 'y': [4, 4, 4, 4, 4], 'w': [5, 4, 3, 2, 1]}\n",
"\n",
"(\n",
" ggplot()\n",
" + geom_point(aes('x', 'y', alpha='v'), data=data_a, color='steelblue', size=8)\n",
" + geom_point(aes('x', 'y', alpha='w'), data=data_b, color='tomato', size=8)\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Two mapped layers sharing scale_alpha(trans=log10)')\n",
")"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-8",
"metadata": {},
"source": [
"## 8. Constant alpha outside [0,1] with a log10-mapped layer\n",
"\n",
"A constant `alpha > 1` or `alpha < 0` is clamped by the renderer regardless of transforms.\n",
"Verify no exception is thrown and the clamping is applied without the transform distorting things."
]
},
{
"cell_type": "code",
"execution_count": 9,
"id": "issue-706-case8a",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 9,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"# alpha=1.5 -> clamped to 1.0 (fully opaque)\n",
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=1.5, color='red') # clamped to 1.0\n",
" + geom_point(aes(alpha='v'), color='black')\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Constant alpha=1.5 (clamped to 1.0) + log10 mapped layer')\n",
")\n"
]
},
{
"cell_type": "code",
"execution_count": 10,
"id": "issue-706-case8b",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 10,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"# alpha=0.0 -> fully transparent (large points invisible by design)\n",
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, alpha=0.0, color='red') # fully transparent\n",
" + geom_point(aes(alpha='v'), color='black')\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Constant alpha=0.0 (fully transparent) + log10 mapped layer')\n",
")\n"
]
},
{
"cell_type": "code",
"execution_count": 11,
"id": "a3b1afeb-d5ff-4313-8cb3-28fe3a52b2c7",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 11,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"# alpha is set via color -> fully transparent (large points invisible by design)\n",
"(\n",
" ggplot(data, aes('x', 'y'))\n",
" + geom_point(size=10, color='red/0') # fully transparent\n",
" + geom_point(aes(alpha='v'), color='black')\n",
" + scale_alpha(trans='log10')\n",
" + ggtitle('Constant alpha=0.0 (fully transparent) + log10 mapped layer')\n",
")\n"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-9",
"metadata": {},
"source": [
"## 9. Other numeric constants with a transform-only fallback\n",
"\n",
"Unlike alpha, some numeric constants can rely on a scale transform even when their own layer has no\n",
"mapper for that aesthetic. A large size constant should still be reduced by a transformed size scale\n",
"when another layer maps size.\n"
]
},
{
"cell_type": "code",
"execution_count": 12,
"id": "issue-706-case9",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 12,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"data_sz = {\n",
" 'x': [1, 2, 3, 4, 5],\n",
" 'y': [2.5, 3, 3.5, 4, 4.5],\n",
" 'v': [1, 2, 5, 10, 1e7],\n",
"}\n",
"\n",
"(\n",
" ggplot(data_sz, aes('x', 'y'))\n",
" + geom_text(aes(label='v'), x=1, size=1e7, color='steelblue')\n",
" + geom_point(aes(size='v'), x=2, color='tomato', alpha=0.5)\n",
" + scale_size(trans='symlog')\n",
" + ggtitle('Constant size=1e7 + scale_size(trans=symlog) - transform fallback is preserved')\n",
")\n"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-10",
"metadata": {},
"source": [
"## 10. Coordinate-derived constant: `slope` is positional already\n",
"\n",
"`slope` is not a scale-mapped visual property like alpha or size. It is treated as positional by\n",
"`Aes.isPositional()`, so it keeps the positional constant path without a separate special case in\n",
"`constantMapperOption`. "
]
},
{
"cell_type": "code",
"execution_count": 13,
"id": "issue-706-case10",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 13,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"data_slope = {\n",
" 'x': [0, 1, 2, 3, 4, 5],\n",
" 'y': [0, 1, 2, 3, 4, 5],\n",
"}\n",
"\n",
"(\n",
" ggplot(data_slope, aes('x', 'y'))\n",
" + geom_point(size=5, color='black')\n",
" + geom_abline(slope=1, intercept=0, color='red', size=1.2)\n",
" + ggsize(760, 260)\n",
" + ggtitle('Constant slope=1 keeps coordinate mapper in a wide plot')\n",
")\n"
]
},
{
"cell_type": "markdown",
"id": "issue-706-section-11",
"metadata": {},
"source": [
"## 11. Regression: huge constant text size must not leak into CSS\n",
"\n",
"The text layer has constant `size=1e7` and no size mapping, while the point layer maps `size` \n",
"and defines `scale_size(trans='symlog')`. The rendered SVG should use the transformed size, \n",
"not a raw `font-size:2.0E7px` declaration."
]
},
{
"cell_type": "code",
"execution_count": 14,
"id": "issue-706-case11",
"metadata": {},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 14,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"values = [3.14 * 10**d for d in range(-7, 7)]\n",
"(\n",
" ggplot({'v': values}, aes(y='v'))\n",
" + geom_point(aes(size='v'), x=0)\n",
" + geom_text(aes(label='v'), x=1, size=1e7)\n",
" + scale_x_continuous(limits=[-.5, 2])\n",
" + scale_y_log10(limits=[10**-7, 10**7])\n",
" + scale_size(trans='symlog')\n",
" + ggsize(400, 600)\n",
" + ggtitle('Regression: constant text size=1e7 + scale_size(trans=symlog)')\n",
")"
]
}
],
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